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SANTHANAM, LAKSHMIIntegrated Security Architecture for Wireless Mesh Networks
PhD, University of Cincinnati, 2008, Engineering : Computer Science and Engineering
Wireless Mesh Networks (WMNs) have revolutionized provisioning of economical and broadband wireless internet service to the whole community of users. The self-configurable and self-healing ability of WMNs has encouraged their rapid proliferation, as adding a mesh router (MR) is as simple as plugging and turning on. The plug-and-play architecture of WMN, however paves way to malicious intruders. An attacker can raise several security concerns, like rogue routers, selfishness, and denial-of-service attacks. Unfortunately, current thrust of research in WMNs, is primarily focused on developing multi-path routing protocols; and security is very much in its infancy. Owing to the hierarchical architecture of WMNs, security issues are multi-dimensional. As mesh routers form the backbone of the network, it is critical to secure them from various attacks. In this dissertation we develop integrated security architecture to protect the mesh backbone. It is important to provide an end-to-end security for mesh clients and hence we design a novel authentication protocol for mutually authenticating mesh clients and mesh routers. The aim of this dissertation is to explore various issues that affect the performance and security of WMNs. We first examine the threat of an active attack like Denial of service attack on MRs and design a cache based throttle mechanism to control it. Next, we develop a MAC identifier based trace table to determine the precise source of a DoS attacker. We then evaluate the vulnerability of WMNs to passive attacks, like selfishness and propose an adaptive mechanism to penalize selfish MRs that discretely drop other’s packets. In order to handle route disruption attacks like malicious route discovery, we design an intelligent Intrusion Detection System. Through extensive simulations, we evaluate effectiveness of our proposed solutions in mitigating these attacks. Finally, we design a light weight authentication protocol for mesh clients using inexpensive hash operations that enables authentication of important control messages and also performs auto-refresh of authentication tokens.

Committee:

Dr. Dharma Agrawal (Advisor)

Keywords:

Wireless mesh networks,; Networks attack in mesh networks,; Selfishness in mesh networks,; Security in mesh networks,; mutual authentication protocol for mesh clients,

Mattioli, Dominik DQuADMESH+: A Quadrangular ADvanced Mesh Generator for Hydrodynamic Models
Master of Science, The Ohio State University, 2017, Civil Engineering
The purpose of this research is to provide a two-dimensional quadrangular mesh-generating tool for modeling shallow water flow within a discontinuous Galerkin finite element framework – a setting where meshes of triangular or quadrilateral composition are easily accommodated and demonstrably advantageous. Prior research and development of ADMESH+ shows that automatic mesh generators can produce high-quality meshes with an appealing gradation of edge size given a minimal set of input, e.g., minimum element size, maximum element size, and domain shoreline and bathymetry. This research aims to expand upon the accomplishments of ADMESH+ by developing a novel method (QuADMESH+) for converting high-quality triangular meshes into quadrangular meshes that retain the geometric and aesthetic facets of the original mesh. Techniques employed in our approach include: triangular-mesh generation techniques used in ADMESH+; a heuristic decision-making algorithm for matching two triangular elements together to form quadrilaterals; a routine for removing any unmatched triangular elements; and common topological operations to improve the quality of quadrilateral elements in the resultant mesh, such as a finite element smoothing algorithm.

Committee:

Ethan Kubatko (Advisor); Alan Zundel (Committee Member); Gil Bohrer (Committee Member); Abdollah Shafieezadeh (Committee Member)

Subjects:

Civil Engineering; Environmental Engineering; Water Resource Management

Keywords:

automatic mesh generation; quadrangular mesh; mixed-element mesh

Wang, JunfangEfficient Positioning Technique for Multi-Interface Multi-Rate Wireless Mesh Networks
PhD, University of Cincinnati, 2010, Engineering and Applied Science: Computer Science and Engineering

Wireless mesh network (WMN) is a strong candidate for the next generation wireless network. A WMN is made up with three types of entities: Internet Gateways (IGWs), mesh routers (MRs), and mesh clients (MCs). IGWs provide interfaces to both the Internet and MRs. MRs together with IGWs form a mesh backbone by interconnecting each other via multi-hop wireless links. MCs access the Internet by setting up connections with MRs. The placement of three entities is one of the fundamental issues that could greatly affect the performance of a WMN. Positioning technique in WMNs aims at optimizing the positions of these nodes to improve network performance and could be further categorized into: IGW placement, MR placement and MC association.

The first part of this dissertation introduces our work over MR placement. MR placement is a strategy that determines the minimal number and positions of MRs that satisfies various constraints such as network coverage, connectivity, Internet traffic demand, etc., for a given network area to be covered by a WMN. Some MR placement strategies may also indicate the appropriate number of interfaces each MR needs as well. A systematic MR placement is the first important step for establishing a WMN with desired network performance efficiently. Our study starts from modeling and formulating the MR placement problem. Then, we analyze the problem in an ideal homogeneous network model, which is characterized by single IGW, identical transmission rate, and MRs could be positioned anywhere in the network region. Hence, we extend the discussion into a more realistic constraint network model: MRs can only be placed in the pre-decided candidate positions; traffic demands is non-uniformly distributed. Furthermore, we deepen our study by taking into accounts the nature of multiple transmission ranges/rates of commercial MRs. We propose a heuristic placement algorithm called ILSearch, which considers both multiple transmission rates and co-channel interference in the constraint network with multiple IGWs. In addition, we develop a virtual force based algorithm: VFPlace, to place MRs in a special constraint network where only candidate areas, rather than specific positions, are known in advance. The numeric results shows the correctness and effectives of our analytical models and proposed algorithms.

The second part of this dissertation presents our work about MC association. MC association strategy targets at helping MCs choose best MRs to establish the connections in the limited space and time. MC association can influence the performance of a WMN to a large extent since it determines how well the mesh backbone, i.e., the associated MRs, can serve MCs. MR's capability for serving MCs varies dynamically due to the changing channel condition, traffic load, and other network parameters. Mobile MCs should attach to MRs that are able to provide best service so as to maximize their own performance. But the determination procedure is constrained by time and space, which makes MCs only able to check partial MRs of the WMN. We map MC association problem as the modified secretary problem. Then, we propose three probabilistic strategies to enhance the possibility that MCs choose the best MRs: opportunistic association, conservative association, and hybrid association. Both statistical analysis and simulations show the conservative strategy outperforms the other two.

Committee:

Dharma Agrawal, DSc (Committee Chair); Kenneth Berman, PhD (Committee Member); Yizong Cheng, PhD (Committee Member); Chia Han, PhD (Committee Member); Wen Ben Jone, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

Mesh Router Placement;Mesh Client Association;Multiply Transmission Rate;Multiply Transmission Range;Virtual Force;Wireless Mesh Network

Wang, YawenTorque Load Effect on Multi-Point Mesh and Dynamics of Right-angle Geared Drives
MS, University of Cincinnati, 2013, Engineering and Applied Science: Mechanical Engineering
Hypoid and bevel gears are widely used in the rear axles of both on and off-highway vehicles, and are often subjected to harmful dynamic responses which cause gear whine noise and structural fatigue problems. The primary goal of this thesis is therefore to develop a more realistic mesh and dynamic model to predict the vibratory response of hypoid and bevel geared systems, and study the effect of different working conditions, e.g. operating speed, torque load, on the dynamic responses of those systems. First, a multi-point hypoid gear mesh model based on 3-dimensional loaded tooth contact analysis is incorporated into a coupled multi-body dynamic and vibration hypoid gear model to predict more detailed dynamic behavior of each tooth pair. To validate the accuracy of the proposed model, the time-averaged mesh parameters are applied to linear time-invariant (LTI) analysis to calculate the dynamic responses, such as dynamic mesh force and dynamic transmission error, which demonstrates good agreement with those predicted by using single-point mesh model. Furthermore, a nonlinear time-varying (NLTV) dynamic analysis is performed considering the effect of backlash nonlinearity and time-varying mesh parameters, such as time-varying mesh stiffness, transmission error, mesh point and line-of-action. One of the advantages of the multi-point mesh model is that it allows the calculation of dynamic responses for each engaging tooth pair, and simulation results for an example case are given to show the time history of the mesh parameters and dynamic mesh force for each pair of teeth within a full engagement cycle. This capability enables the analysis of durability of the gear tooth pair and more accurate prediction of the system response. Secondly, to have more insights on the load dependent mesh parameters and dynamic responses of the hypoid and spiral bevel geared systems, a load dependent mesh model is developed by using 3-dimensional loaded tooth contact analysis (LTCA). The contact ratio and time-varying mesh parameters including the mesh stiffness, transmission error, mesh point and line-of-action of the mesh force are examined within a wide torque range. Then a nonlinear multi-body dynamic analysis is performed considering the effect of backlash nonlinearity. Simulation results show that the contact ratio and mesh stiffness generally increases as the toque load increases. The effect of torque load on dynamic mesh force is found to be frequency dependent due to the resonance frequency shifts and peak magnitude changes. This study provides an in-depth understanding of the dynamic tooth load sharing and the dynamic behaviors for hypoid and bevel geared systems in terms of change in operating load. Therefore, the proposed model can be employed to assist in gear design optimization.

Committee:

Teik Lim, Ph.D. (Committee Chair); J. Kim, Ph.D. (Committee Member); David Thompson, Ph.D. (Committee Member)

Subjects:

Mechanics

Keywords:

Mulit-point mesh;Torque load effect;Gear dynamics;Hypoid gear;Dynamic mesh force

Zulkefli, Zamir Aimaduddin BinMITIGATION OF GEAR MESH-FREQUENCY VIBRATIONS UTILIZING A HYDROSTATIC BEARING
Doctor of Philosophy, Case Western Reserve University, 2013, EMC - Mechanical Engineering

In the current environment of noise abatement, high frequency noises are especially objectionable. For gear drives, high frequency noises are symptoms of gear mesh-frequency vibrations which are ever-present due to the imperfect conjugate action between the gears. These vibrations are then transferred to the gear housing to be emitted as noise. The vibration energy flow can be disrupted, for example using a hydrostatic bearing as a low pass filter of vibrations while still preserving the positioning accuracy of the gear drive.

Hydrostatic bearings are a class of fluid bearings consisting of externally pressurized fluid trapped in a recess to provide the necessary bearing support. Previous research has assumed the incompressibility of the working fluid in a hydrostatic bearing. In practice, the working fluid is not incompressible and the effect is not necessarily insignificant. Using the compressibility of the working fluid and the unique properties of a hydrostatic bearing, a low-pass filtering effect on the gear mesh-frequency vibrations can generated. This low-pass filter allows low frequency vibrations to be transmitted while high frequency vibrations are attenuated. The vibration attenuation disrupts its transmission to the gear housing and prevents its conversion into high frequency acoustic noise.

Models to predict this low-pass filtering effect were developed using a control volume approach for constant flow and capillary flow compensation schemes while the compressibility of the working fluid is incorporated using the bulk modulus. A linear differential equation was then obtained. Using the solution to the differential equation and convolution, an expression for the frequency response of the transmitted dynamic pressure was developed. In addition, a proof of concept experiment was designed and implemented to validate the theoretical models. The experimental data shows similar attenuation of the transmitted dynamic pressure according to theoretical predictions for both the constant flow and capillary compensated flow models.

Committee:

Maurice Adams, PhD (Committee Chair); Dario Gasparini, PhD (Committee Member); Jaikrishnan Kadambi, PhD (Committee Member); Joseph Mansour, PhD (Committee Member); Robert White, PhD (Committee Member)

Subjects:

Engineering; Mechanical Engineering

Keywords:

Hydrostatic Bearing; Gear Mesh-Frequency; Gear Mesh Vibrations

Fan, ZongyueDynamic Adaptive Mesh Refinement Algorithm for Failure in Brittle Materials
Master of Sciences, Case Western Reserve University, 2016, EMC - Mechanical Engineering
The present work is aimed at developing a dynamic adaptive mesh refinement (DAMR) method for the study of failure mechanisms in brittle materials within the eigenfracture framework. A mesh refinement method based on boundary representation technique (B-rep) and Delaunay triangulation is developed. In addition, a flip algorithm is employed to guarantee the quality of the refined mesh. The mesh refinement algorithm is verified in an example of static adaptive mesh generation of polycrystalline structures that are created by using Voronoi tessellation. Furthermore, the DAMR method is built upon the combination of the adaptive mesh refinement algorithm and the eigenfracture approach. In the DAMR, the energy release rate G is used as the adaption. Finally, the DAMR method is validated by comparing to mode-I and mixed mode fracture experiments on concrete materials. The simulation results show excellent agreement with experimental measurements and more accurate predictions than the original eigenfracture approach.

Committee:

Bo Li (Committee Chair); Vikas Prakash (Committee Member); John Lewandowski (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

dynamic adaptive mesh refinement; eigenfracture; finite elements; mesh generation; brittle material; polycrystalline material;

Cilwa, Katherine ElizabethSurface Plasmon Polaritons and Single Dust Particles
Doctor of Philosophy, The Ohio State University, 2011, Chemistry

Square nickel mesh perforated with micron scale holes exhibits extraordinary transmission due to propagating surface plasmon polaritions (PSPP) combined with cavity modes. Propagating surface plasmon resonances are known to disperse with the angle of incident light and such experiments yield rich information regarding the plasmonics of the material. More accurate polarized Gamma X dispersion is presented within, as well as the first polarized Gamma M dispersion of square nickel mesh. Calculation of resonance positions within these experiments predicts an effective index of refraction for the asymmetric coupled surface plasmon polaritons to have a value of n’eff, = 1.043. Gamma P and Gamma Q Dispersion of hexagonal mesh is presented and the coupling of asymmetric plasmonic surfaces examined. Calculations allowing interactions between PSPP states of square mesh are compared with experimental results and traditional predictions of mesh, PSPP transmission maxima; explaining variation from experimental results and traditional predictions and illustrating the polariton, or mixed state, nature of PSPPs. Lastly, scatter free infrared spectra of sixty-three individual micron scale dust particles are presented by placement of each particle in a hole of plasmonic square nickel mesh. The constituents of each particle and the process of quantification of materials is examined by use of Mie scattering, Lorentz dispersion, and Bruggeman effective medium theories. The propagation lengths for PSPP resonances on such mesh are poor (~1-2 hole-to-hole spacings), compared to smooth metal predictions or less absorbing metals, making this mesh ideal for studying individual particles. The PSPPs funnel light through the particles, but they are effectively isolated so long as the neighboring holes are empty. Saturation of absorption peaks at this scale are demonstrated.

Committee:

James Coe, V (Advisor); Singer Sherwin (Committee Member); Wyslouzil Barbara (Committee Member)

Subjects:

Physical Chemistry

Keywords:

surface plasmon polaritions; square mesh; hexagonal mesh; surface plasmon polariton interactions; individual dust particles; particulate matter; micron particles

Cilwa, Katherine E.Surface Plasmons Polaritons and Single Dust Particles
Doctor of Philosophy, The Ohio State University, 2011, Chemistry
Square nickel mesh perforated with micron scale holes exhibits extraordinary transmission due to propagating surface plasmon polaritions (PSPP) combined with cavity modes. Propagating surface plasmon resonances are known to disperse with the angle of incident light and such experiments yield rich information regarding the plasmonics of the material. More accurate polarized Gamma X dispersion is presented within, as well as the first polarized Gamma M dispersion of square nickel mesh. Calculation of resonance positions within these experiments predicts an effective index of refraction for the asymmetric coupled surface plasmon polaritons to have a value of n’eff = 1.043. Gamma P and Gamma Q dispersion of hexagonal mesh is presented and the coupling of asymmetric plasmonic surfaces examined. Calculations allowing interactions between PSPP states of square mesh are compared with experimental results and traditional predictions of mesh, PSPP transmission maxima; explaining variation from experimental results and traditional predictions and illustrating the polariton, or mixed state, nature of PSPPs. Lastly, scatter free infrared spectra of sixty-three individual micron scale dust particles are presented by placement of each particle in a hole of plasmonic square nickel mesh. The constituents of each particle and the process of quantification of materials is examined by use of Mie scattering, Lorentz dispersion, and Bruggeman effective medium theories. The propagation lengths for PSPP resonances on such mesh are poor (~1-2 hole-to-hole spacings), compared to smooth metal predictions or less absorbing metals, making this mesh ideal for studying individual particles. The PSPPs funnel light through the particles, but they are effectively isolated so long as the neighboring holes are empty. Saturation of absorption peaks at this scale are demonstrated.

Committee:

James Coe, PhD (Advisor); Sherwin Singer, PhD (Committee Member); Barbara Wyslouzil, PhD (Committee Member)

Subjects:

Atmospheric Chemistry; Atmospheric Sciences; Chemistry; Condensed Matter Physics; Environmental Education; Environmental Geology; Environmental Health; Environmental Management; Environmental Science; Environmental Studies; Geochemistry; Mineralogy; Molecular Physics

Keywords:

surface plasmon; surface plasmon polariton; dispersion; Mie; scattering; Lorentz; Bruggeman; micron; particles; particulate; PM10; dust; single particle; interaction; IR; infrared; mesh; hole arrays; extraordinary transmission; hexagonal; absorption

Yang, JunyiNonlinear Dynamics of Driveline Systems with Hypoid Gear Pair
PhD, University of Cincinnati, 2012, Engineering and Applied Science: Mechanical Engineering

This dissertation research focuses on evaluating the nonlinear dynamics of driveline systems employed in motor vehicles with emphasis on characterizing the excitations and response of right-angle, precision hypoid-type geared rotor structure. The main work and contribution of this dissertation is divided into three sections. Firstly, the development of an asymmetric and nonlinear gear mesh coupling model will be discussed. Secondly, the enhancement of the multi-term harmonic balance method (HBM) is presented. Thirdly and as the final topic, the development of new dynamic models capable of evaluating the dynamic coupling characteristics between the gear mesh and other driveline structures will be addressed.

A new asymmetric and nonlinear mesh model will be proposed that considers backlash, and the fact that the tooth surfaces of the convex and concave sides are different. The proposed mesh model will then be fed into a dynamic model of the right-angle gear pair to formulate the dimensionless equation of motion of the dynamic model. The multi-term HBM will be enhanced to simulate the right-angle gear dynamics by solving the resultant dimensionless equation of motion. The accuracy of the enhanced HBM solution will be verified by comparison of its results to the more computationally intensive direct numerical integration calculations. The stability of both the primary and sub-harmonic solutions predicted by applying multi-term HBM will be analyzed using the Floquent Theory. In addition, the stability analysis of the multi-term HBM solutions will be proposed as an approximate approach for locating the existence of sub-harmonic and chaotic motions.

In this dissertation research, a new methodology to evaluate the dynamic interaction between the nonlinear hypoid gear mesh mechanism and the time-varying characteristics of the rolling element bearings will also be developed. The time-varying mesh parameters will be obtained by synthesizing a 3-dimensional loaded tooth contact analysis (TCA) results. The time-varying stiffness matrix approach will be used to represent the dynamic characteristics of the rolling element bearings.

An overall nonlinear dynamic model of the hypoid gear box considering elastic housing structure will be developed as well. A lumped parameter model of the flexible housing will be extracted form an appropriate set of frequency response functions through modal parameter identification method. In order to obtain the rotational coordinates, a rigid body interpolation of the translational responses at the bearing locations on the housing structure will be applied. The reduced model will be then coupled with the hypoid gear-shaft-bearing assembly model by applying a proposed dynamic coupling procedure.

Finally, a hypoid geared rotor system model considering the propeller shaft flexibility will be established. The propeller shaft bending flexibility will be modeled as lumped parameter model through using the component mode synthesis (CMS). The torsional flexibility of propeller shaft will be simplified as a torsional spring connecting the inertia of moment of engine and pinion. Physically, the pinion input shaft is driven by the propeller shaft through a universal joint, which will be modeled as a flexible simple supported boundary condition as well as fluctuating rotation speed and torque excitation.

Committee:

Teik Lim, PhD (Committee Chair); Sundaram Murali Meenakshi, PhD (Committee Member); Dong Qian, PhD (Committee Member); David Thompson, PhD (Committee Member)

Subjects:

Mechanics

Keywords:

Nonlinear gear dynamics;Multi-term harmonic balance;Asymmetric mesh;Gear backlash;Nonlinear driveline dynamics;Sub-harmonic and chaotic motions;

Joshi, SaugatFast and Efficient Mutual Authentication in Wireless Mesh Networks (WMNs)
MS, University of Cincinnati, 2011, Engineering and Applied Science: Computer Science

Through the evolvement of high speed internet, Wireless mesh networks (WMNs) have become one of the most exciting and promising technology for providing high bandwidth features to its users. Along with the advancement of internet, the demand for enhanced capacity and higher bandwidth requirement have strived over time to meet the requirements of the Quality of Service (QoS) in WMNs. Various factors do affect the desired Qos for WMNs. In this thesis, we focus on the key generation scheme for authentication between various entities of the network to establish a secure communication between them, while taking into consideration the QoS requirements set by the benchmark. The key generation scheme discussed here is decentralized and hierarchal in nature which enables a pair of entity (e.g., servers and clients) to share a common key for a secure communication. Moreover, the scheme addresses the issue of the high speed mobility of the clients stations (STAs) from one domain to another domain, i.e. handoff between various inter- domain and intra- domain Access Points (APs). It is necessary that the STAs do not require excessive overhead during the handoff procedure. The schemes discussed enables faster and secure key generation and agreement scheme between the entities of the network during the handoff procedure.

The key generation scheme is distributed in nature. The higher level hierarchy namely the Internet Gateways (IGWs) or the authentication, authorization and accounting (AAA) servers such as RADIUS, generate a multi variate symmetric polynomial function and exchange the information among them such that none of them have a complete knowledge of the entire generated function. As the functions are passed to the lower level hierarchical entities such as Mesh access points (MAPs), the function further reduces providing only legitimate information to them. The process continues until the lowest level of the hierarchy (STAs or clients) is reached where the entities will be able to deduce a secure key for the communication. We refer to this as a distributed mechanism or a distributed authenticated key establishment (AKE) scheme based on hierarchal multi-variable symmetric functions (HMSF). Since, the deduced key is obtained from distributed scheme and below various levels none of the entities have a complete knowledge to reverse engineer the original function used in the generation process. Using the distributed authenticated key establishment scheme the STAs and MAPs could authenticate among themselves without any assistance from the higher hierarchy entities, thus saving the communication overhead time and the delay involved in authentication by getting back to the servers hence maintaining the required QoS.

Committee:

Dharma Agrawal, DSc (Committee Chair); Raj Bhatnagar, PhD (Committee Member); Yizong Cheng, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

Wireless Mesh Networks;Authentication;symmetric;polynomial;handoff;security

Drabu, YasirGateway Placement And Fault Tolerance In QoS Aware Wireless Mesh Networks
PHD, Kent State University, 2010, College of Arts and Sciences / Department of Computer Science
Wireless Mesh Networks (WMN's), in the form of WiFi (802.11x) or WiMax (802.16x), or their integrations have been proposed as an effective communication alternative for ubiquitous last mile wireless broadband access. They can be viewed as a hybrid between traditional cellular, point-to-point wireless systems, and ad-hoc networks. They offer more flexibility, mobility, coverage and expandability compared to their traditional counterparts at the expense of complex architecture and deployment structure. Though WMNs hold great promise in abetting network ubiquity, there still remain several challenges in the design and development of WMN's to support diverse services with different quality of service (QoS) requirements and large scale deployment. The focus of this dissertation is to address some of the core issues that directly affect the QoS in terms of delay, throughput, and fault tolerance. First we look at the deployment problem of the placement of wired gateways. This aspect of WMNs has a significant impact on the network's throughput performance, cost and capacity to satisfying the quality of service requirements. In the context of gateway placement, the QoS is influenced by the number of gateways, the number of nodes served by each gateway, the location of the gateways, and the relay load on each wireless router. While finding an optimal solution to simultaneously satisfy all the above constraints is known to be an NP-hard problem, near optimal solutions can be found within the feasibility region in polynomial time using various heuristic methods. In the initial part of this dissertation, we first present a near optimal heuristics algorithm for gateway placement that facilitates QoS provisioning and fault tolerance in WMNs. We then investigate fault tolerance and recovery problems in WMNs. We present a fault recovery algorithm that can exploit the known geometry of a regular cellular mesh network. While keeping the QoS metrics intact, we consider a post-deployment fault recovery algorithm and pre-deployment fault tolerance planning.

Committee:

Hassan Peyravi, PhD (Advisor); Javed Khan, PhD (Committee Member); Feador Dragan, PhD (Committee Member); Kazim Khan, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

wireless mesh networks; deployment algorithms; fault tolerant provisioning

Horchler, Andrew de SalleDesign of Stochastic Neural-inspired Dynamical Architectures: Coordination and Control of Hyper-redundant Robots
Doctor of Philosophy, Case Western Reserve University, 2016, EMC - Mechanical Engineering
Effective control of soft and hyper-redundant devices, such as worm-like robots, requires many degrees of freedom to be coordinated while adapting the sequential pattern of activity based on sensory feedback. A striking feature of biological pattern generators is their ability to respond immediately to multi-sensory perturbations by modulating the dwell time at a particular phase of activity without disrupting overall coordination. This dissertation presents new mathematical tools for the design and analysis of a dynamical architecture that can be used to responsively coordinate many degrees of freedom: stable heteroclinic channels (SHCs). For SHC cycles, the addition of stochastic noise results in oscillation with a regular mean period. A new soft robot, Compliant Modular Mesh Worm, which utilizes individually actuated segments to produce peristaltic locomotion, has been constructed as a platform to evaluate SHC control. The robot's modular mesh allows components to be easily interchanged to vary stiffness. Experiments were performed to characterize the actuated mesh and study how the interaction between friction, compliance, and the precision of segment control impacts locomotion performance. A real time SHC controller that allows predictable noise-driven variability of the robot's locomotion pattern was developed and evaluated. These results will be useful for the design and control of future peristaltic devices.

Committee:

Roger Quinn (Advisor); Hillel Chiel (Advisor); Joseph Mansour (Committee Member); Cenk Cavusoglu (Committee Member)

Subjects:

Biology; Biomechanics; Engineering; Mechanical Engineering; Neurosciences; Robotics; Robots

Keywords:

robot, biological inspiration, worm, earthworm, peristalsis, locomotion, soft robotics, compliant, modular, mesh, computational neuroscience, stochastic, noise, SDE, SHC, stable heteroclinic channels, simulation, pattern generation, dynamics

Prathapani, AnooshaIntelligent Honeypot Agents for Detection of Blackhole Attack in Wireless Mesh Networks
MS, University of Cincinnati, 2010, Engineering and Applied Science: Electrical Engineering

A Wireless Mesh Network (WMN) is a promising means to provide low-cost broadband Internet access. The routing protocols naively assume all nodes in the network to be non-malicious. The open architecture of WMN, multi-hop nature of communication, different management styles, and wireless communication paves way for malicious attackers. The attackers can exploit hidden loopholes in the multipath mesh routing protocol to conduct a suction attack called a “blackhole attack”. The attacker can falsify routing metric such as hop count, shorten transmission time to reach any destination and thereby suck the network traffic.

We propose a novel strategy by employing mobile honeypot agents that utilize their topological knowledge and detect such spurious route advertisements. They are deployed as roaming software agents that tour the network and lure attackers by sending Route Request (RREQ) advertisements. We first examine the threat of an active Blackhole attack, and then, using our intelligent Honeypot mechanism, we try to control it. We collect valuable information on attacker’s strategy from the intrusion logs gathered at the honeypot. We finally evaluate the effectiveness of proposed architecture using simulation in ns-2 for random topology and grid topology. The performance of the proposed detection approach has shown the encouraging results. The performance of the proposed detection scheme is shown to be increased by 80% for grid topology and 77% for random topology.

Committee:

Dharma Agrawal, DSc (Committee Chair); Carla Purdy, PhD (Committee Member); Wen Ben Jone, PhD (Committee Member)

Subjects:

Electrical Engineering

Keywords:

AODV; BLACKHOLE; HONEYPOTS; MALICIOUS; SPOOFED; WIRELESS MESH NETWORKS

Prakash, AbhinavAnonymous and Secure Communication in a Wireless Mesh Network
MS, University of Cincinnati, 2012, Engineering and Applied Science: Computer Science

With the rapid advancement of different types of wireless technologies the problem arose of combining them together to provide improved bandwidth and enhanced throughput. The answer came out in the form of a Wireless Mesh Network (WMN). A typical WMN is made up of mesh routers and mesh clients where mesh routers have somewhat limited mobility and they form the backbone of the network whereas mesh clients are allowed to be highly mobile or completely stationary or somewhere in between. This forms a very versatile network which allows clients with different levels of mobility, interface and bandwidth requirements to be a part of the same network. The communication can be achieved by directly communicating with the router by being in its range or in an ad hoc fashion through several hops. A WMN is mainly designed to be self-configured and self-adjusting dynamically. This ensures large network coverage with minimum infrastructure requirements, hence low cost. Although a WMN gives multifold advantages it is also vulnerable to several security and privacy threats being a dynamic open medium. Different types of clients such as laptops, cell phones, smart devices can join or leave the network anytime they wish. This opens up issues like fake registrations and packet sniffing.

This work deals with the issues of security and privacy separately in two parts in great detail by simulating countermeasures for different kinds of attacks in a WMN. The first part mainly deals with creating a perfectly secure network for safe communication by using a bi-variate polynomial scheme for low overheads instead of a public-private key mechanism. The second part deals with making any communication in the network anonymous by hiding the node initiating the session by using redundancy at the cost of some associated overheads.

Committee:

Dharma Agrawal, DSc (Committee Chair); Yizong Cheng, PhD (Committee Member); Chia Han, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

Mesh Networks; Security; Onion Routing; Bivariate Polynomial Function; Backbone; Hybrid Networks

Kripakaran, RamakrishnanEffective Strategies for Mesh Router Selection in Wireless Mesh Networks
MS, University of Cincinnati, 2010, Engineering : Computer Science
Wireless Mesh Network (WMN) is a developing technology which envisions a wireless backbone architecture (in place of the existing wired) to aid in providing internet connectivity to users at the residential and commercial level. In a WMN, the density of Mesh Clients (MCs) and the rate of traffic generated from each client are not uniformly distributed. Also, the traffic routes from a Mesh Router (MR) to the Internet GateWay (IGW) are multi-hop and multi-path in nature. Due to these factors, each MR has a different performance. For large scale WMN, maintaining such information about each MR in a centralized manner is not a practical and scalable solution. In addition, when new MCs enter the WMN they have little or no information about the performance of MRs. With scarce information, it is difficult for a MC to select a MR which can provide the best service. Therefore, MCs must directly request each MR in its vicinity to obtain information that can help make this decision. Since MCs have the freedom to select a MR of their choice, examining all nearby MR increases the chance of selecting a better MR suited for their application. However, often a MC has limited time available for selecting the MR. We propose three strategies that a MC can implement in making the selection of the MR - opportunistic, conservative and calculatingly-opportunistic. We study the performance of these strategies theoretically and statistically. We obtain the closed form solution for the conservative strategy which proves to be the best of the three strategies. We also identify the network parameter that can be used to rank the performance of an MR. We perform extensive network simulations to evaluate the performance of the strategies with various network configurations.

Committee:

Dharma Agrawal, DSc (Committee Chair); Fred Annexstein, PhD (Committee Member); Chia Han, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

Wireless Mesh Networks

He, BingArchitecture Design and Performance Optimization of Wireless Mesh Networks
PhD, University of Cincinnati, 2010, Engineering : Computer Science and Engineering

Wireless Mesh Network (WMN) is a promising wireless technology in providing high-bandwidth Internet access over a specific coverage area, with relative lower investment cost as compared to traditional access network. In a WMN, a mobile client (MC) can access the Internet through a wireless backbone formed by wireless Mesh Routers (MRs) which are interconnected in a multi-hop fashion while some MRs known as Internet Gateways (IGWs) act as the communication bridges between the wireless backbone and the Internet. The design of the network architecture is a fundamental issue for a WMN and is critical in determining the network performance and providing Quality of Service (QoS) for end users, and thus should be addressed carefully.

A unique characteristic of a WMN is the IGW oriented Internet traffic. Thus, the deployment of IGW is the key problem in the network design, and is investigated in this dissertation. Two IGW oriented network architecture are analyzed, and corresponding QoS requirements and constraints are evaluated. The IGW deployment problem is then formulated as a multiple objectives optimization problem. Besides the linear program approach, some heuristic algorithms are proposed and evaluated. Extensive simulations show the effectiveness of proposed solutions.

To improve the performance of a given WMN, load balancing between different IGW domains is also investigated. A fairness between IGWs domains improves the network performance and provides a better QoS for end users. The fairness index is defined for both homogenous and heterogeneous WMNs. A distributed load balancing scheme is proposed, and three load balancing algorithms based on diffusion methodology are introduced in the proposed scheme.

Authenticated key establishment (AKE) schemes enable two entities (e.g., a client and a server) to share common communication keys in an authentic way. Due to mobility of mesh clients (MCs), a WMN needs have a fast and efficient authentication and key establishment scheme to provide adequate security in client's handoff while meeting the Quality of Service (QoS) requirements. In this dissertation, we discuss the authentication performance requirements imposed by the unique WMN characteristics. Distributed authenticated key establishment schemes are proposed based on hierarchical multi-variable symmetric functions (HMSF) and identity-based cryptography (IBC) respectively, which enable fast key agreement and mutual authentication between network entities in a WMN. In the distributed authenticated key establishment scheme, network entities in a WMN such as MCs and mesh access points (e.g. mesh routers) can authenticate each other and establish pairwise communication keys without any interaction from a centralized authentication center, while substantially reducing the communication overhead and the authentication delay.

Committee:

Dharma Agrawal, DSc (Committee Chair); Kenneth Berman, PhD (Committee Member); Chia Han, PhD (Committee Member); Kelly Cohen, PhD (Committee Member); Ernest Hall, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

Wireless Mesh Networks;Internet Gateway;Load Balancing;Authenticated Key Establishment;Symmetric Polynomial;Identity-based Cryptography

Heminger, Michael AlanDynamic Grid Motion in a High-Order Computational Aeroacoustic Solver
Master of Science in Mechanical Engineering, University of Toledo, 2010, Mechanical Engineering

In this work, moving meshes will be employed to solve unsteady computational problems, while maintaining high-order, and high-accuracy. The main problem of interest is that of a plunging piston. The plunging piston problem, first presented in the First Workshop for Computational Aeroacoustics.

Typically, computational aeroacoustics is seperate from aeroelasticity, a field where moving surfaces is integral. This project will join the two field, attempting to resolve propagating waves from a moving boundary. While this particiular problem has been attempted before, it was done using boundary conditions.

This project’s main goal is to bridge the gap between computation fluid dynamic disciplines, creating a general standalone mesh morpher, enabling a new breed of acoustic problems to be solved.

To do this, a highly efficient method of moving the mesh will need to be developed. Since the code uses high-order schemes to resolve the small sound waves, the mesh mover must be methods which keep the grid metrics continuous and smooth.

Committee:

Ray Hixon, Ph.D. (Advisor); Abdollah Afjeh, Ph.D. (Committee Member); Chunhua Sheng, Ph.D. (Committee Member)

Subjects:

Acoustics; Engineering; Fluid Dynamics; Mechanical Engineering

Keywords:

cfd; caa; computational fluid dynamics; aeroacoutics; mesh; grid; deformation; morphing; fluid structure interaction; piston

Conroy, Colton J.ADmesh: An ADvanced Mesh Generator for Hydrodynamic Models
Master of Science, The Ohio State University, 2010, Civil Engineering
The purpose of this research is the development and implementation of a 2D advanced automatic mesh generator for hydrodynamic models. Starting with only a target element size and points defining the boundary and bathymetry/topography of the domain, the goal of the mesh generator is to automatically produce a high- quality mesh from this minimal set of input. From the geometry provided, properties such as local features, curvature of the boundary, bathymetric/topographic gradients, and approximate flow characteristics can be extracted, which are used to determine local element sizes. The result is a high quality mesh, with the correct amount of refinement where it is needed to resolve all of the geometry and flow characteristics of the domain. Techniques incorporated include the use of the so-called signed distance function, which is used to determine critical geometric properties, the approximation of piecewise linear coastline data by smooth periodic cubic splines, a so-called mesh function used to determine element sizes and control the size ratio of neighboring elements, and a force-displacement method which iterates to improve the element quality of the mesh. Meshes of coastal domains created by the new mesh generator are presented.

Committee:

Ethan J. Kubatko, PhD (Advisor); Sandip Mazumder, PhD (Committee Member); Gil Bohrer, PhD (Committee Member)

Subjects:

Civil Engineering; Computer Engineering; Environmental Engineering; Fluid Dynamics

Keywords:

mesh generator; computational hydrodynamics; fluid dynamics; ADCIRC model; distmesh

Xiang, ChangshengA New Way for Mapping Texture onto 3D Face Model
Master of Science (M.S.), University of Dayton, 2015, Electrical Engineering
Adding texture to an object is extremely important for the enhancement of the 3D model's visual realism. This thesis presents a new method for mapping texture onto a 3D face model. The complete architecture of the new method is described. In this thesis, there are two main parts, one is 3D mesh modifying and the other is image processing. In 3D mesh modifying part, we use one face obj file as the 3D mesh file. Based on the coordinates and indices of that file, a 3D face wireframe can be displayed on screen by using OpenGL API. The most common method for mapping texture onto 3D mesh is to do mesh parametrization. To achieve this goal, a perspective-projection method is used to map 3D mesh to a 2D plane. To improve the degree of the accuracy, we separates the 3D mesh into three pieces based on three different view positions from left to right. In image processing part, we extracted the face information from the green back- ground images by using image segmentation. Because of the three face images from different view positions, so they have different light illumination. In this thesis, a button controller was made to control the light illumination of three parts separately. The image blending method was used to reduce the texture seam between two different parts of the mesh. The proposed method in this thesis is new way to add detail to a 3D model. It provides a valid texture mapping, also satisfies the man-machine interaction exactly. Even if the images are taken under the different illumination, users can use keyboard to change its illumination for color matching. This new way provides a new method to parametrize and modify the mesh so as to be used for texture mapping.

Committee:

John S. Loomis, Dr. (Advisor)

Subjects:

Computer Engineering; Computer Science; Electrical Engineering

Keywords:

texture mapping; 3D face model; mesh parametrization; image processing; OpenGL; OpenCV

Mamidisetty, Kranthi KumarGeneralizing Contour Guided Dissemination in Mesh Topologies
Master of Science, University of Akron, 2008, Electrical Engineering
Wireless mesh topologies are important for a variety of engineered systems. Despite the mesh connectivity, where every node is connected to several neighbors, the number of shortest paths between a pair of nodes is limited by the relative locations of the nodes. Prior work in this area has resulted in the characterization of the structure of the shortest paths between a pair of nodes in a regular mesh topology in which each node has eight neighbors. This thesis presents new results that characterize the structure of the union of all the shortest paths between a pair of nodes in mesh topologies where each node has three, four, or six neighbors. When a source sends M messages to the sink, and every node spreads the messages over every available shortest path uniformly, it is shown that nodes along one shortest path will always handle more messages than the nodes along other shortest paths. Optimal rules which ensure that nodes at a same distance from the source along different paths handle roughly the same number of messages, are presented. Simulation results that validate the analytical conclusions are also presented. In the future, similar methods for dissemination can be developed for general topologies.

Committee:

Shivakumar Sastry, PhD (Advisor); James Grover, PhD (Committee Member); S.I. Hariharan, PhD (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Contour; Dissemination; Mesh Topologies; Routing; Neighbor; QoS

Hua, XiaHypoid and Spiral Bevel Gear Dynamics with Emphasis on Gear-Shaft-Bearing Structural Analysis
MS, University of Cincinnati, 2010, Engineering and Applied Science: Mechanical Engineering

Hypoid and spiral bevel gears, used in the rear axles of cars, trucks and off-highway equipment, are subjected to harmful dynamic response which can be substantially affected by the structural characteristics of the shafts and bearings. This thesis research, with a focus on gear-shaft-bearing structural analysis, is aimed to develop effective mathematical models and advanced analytical approaches to achieve more accurate prediction of gear dynamic response as well as to investigate the underlying physics affecting dynamic response generation and transmissibility. Two key parts in my thesis are discussed below.

Firstly, existing lumped parameter dynamic model has been shown to be an effective tool for dynamic analysis of spiral bevel geared rotor system. This model is appropriate for fast computation and convenient analysis, but due to the limited degrees of freedom used, it may not fully take into consideration the shaft-bearing structural dynamic characteristics. Thus, a dynamic finite element model is proposed to fully account for the shaft-bearing dynamic characteristics. In addition, the existing equivalent lumped parameter synthesis approach used in the lumped parameter model, which is key to representing the shaft-bearing structural dynamic characteristics, has not been completely validated yet. The proposed finite element model is used to guide the validation and improvement of the current lumped parameter synthesis method using effective mass and inertia formulations, especially for modal response that is coupled to the pinion or gear bending response. Secondly, a new shaft-bearing model has been proposed for the effective supporting stiffness calculation applied in the lumped parameter dynamic analysis of the spiral bevel geared rotor system with 3-bearing straddle-mounted pinion configuration. Also, based on 14 degrees of freedom lumped parameter dynamic model and quasi-static three-dimensional finite element tooth contact analysis program, two typical shaft-bearing configuration used in automotive application, that are the 3-bearing straddle mounted pinion configuration and the 2-bearing overhung mounted pinion configuration, are compared for their different contribution to the spiral bevel gear mesh and dynamics. Parametric study is also performed to analyze the effect of shaft-bearing configuration on spiral bevel gear mesh and dynamics.

Committee:

Teik Lim, PhD (Committee Chair); Ronald Huston, PhD (Committee Member); David Thompson, PhD (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

Hypoid and Spiral Bevel Gear;Gear Mesh and Dynamics;Shaft-bearing;Finite Element;Lumped Parameter;Parameter Synthesis

Gaur, AmitSecured Communication in Wireless Sensor Network (WSN) and Authentic Associations in Wireless Mesh Networks
MS, University of Cincinnati, 2010, Engineering and Applied Science: Computer Science
Wireless sensors are low power devices with small transmission range, restricted computation power, limited amount of memory and with portable power supply. Wireless Sensor Network (WSN) is a collection of such sensors where the number of sensors can vary from few hundreds to thousands. Performing secure pair-wise communication between sensors is a really difficult task due to inherent characteristics such as lack of any fixed infrastructure. As memory and power consumption are most stringent requirements for these devices, use of conventional techniques for secured communication are totally out of question. This thesis introduces scheme that enables a complete pair-wise secure connectivity between any two adjacent sensor nodes in spite of using small key ring (KR) for sensors. The Proposed Scheme (ELKPD) doesn't require any additional hardware while providing keys to the sensors irrespective of their location. Also, proposed scheme is easily scalable which allows enables addition of sensor nodes without any computational or hardware overheads. Due to the varying degree of mobility of Mesh Clients has provided much more flexibility in Wireless Mesh Networks. And establishing an Authentic Association among entities is a non -trivial problem. In this thesis, we introduce a Polynomial Based scheme which not only provides high pair-wise connectivity, low communication and storage overhead and high scalability but also makes on the fly Authentic Association feasible. The proposed scheme is also observed to be resilient against both the traffic analysis and the node capture attacks.

Committee:

Dharma Agrawal, DSc (Committee Chair); Raj Bhatnagar, PhD (Committee Member); Carla Purdy, C, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

security;wireless sensor networks;key-predistribution;wireless mesh networks;bi-variate polynomials

Xu, HaiDevelopment of a generalized mechanical efficiency prediction methodology for gear pairs
Doctor of Philosophy, The Ohio State University, 2005, Mechanical Engineering
In this study, a general methodology is proposed for the prediction of friction-related mechanical efficiency losses of gear pairs. This methodology incorporates a gear contact analysis model and a friction coefficient model with a mechanical efficiency formulation to predict the gear mechanical efficiency under typical operating conditions. The friction coefficient model uses a new friction coefficient formula based on a non-Newtonian thermal elastohydrodynamic lubrication (EHL) model. This formula is obtained by performing a multiple linear regression analysis to the massive EHL predictions under various contact conditions. The new EHL-based friction coefficient formula is shown to agree well with measured traction data. Additional friction coefficient formulae are obtained for special contact conditions such as lubricant additives and coatings by applying the same regression technique to the actual traction data. These coefficient of friction formulae are combined with a contact analysis model and the mechanical efficiency formulation to compute instantaneous torque/power losses and the mechanical efficiency of a gear pair at a given position. This efficiency prediction methodology is applied to both parallel axis (spur and helical) and cross-axis (spiral bevel and hypoid) gears. In the case of hypoid gears, both face-milling and face-hobbing processes are considered, and closed-form expressions for the geometric and kinematic parameters required by the efficiency model are derived. The efficiency prediction model is validated by comparing the model predictions to a set of high-speed spur gear efficiency measurements covering several gear design and surface treatment variations. The differences between the predicted efficiency values and the measured ones are consistently within 0.1 percent. Influence of basic gear design parameters, tooth modifications, operating conditions, surface finish and treatments, lubricant properties, and manufacturing and assembly errors on mechanical efficiency of both parallel-axis and cross-axis gears are investigated. At the end, a set of guidelines is provided on how to improve mechanical efficiency of gear pairs through design, surface engineering and lubricant solutions.

Committee:

Ahmet Kahraman (Advisor)

Subjects:

Engineering, Mechanical

Keywords:

Mesh friction; Efficiency; Lubrication; EHL; Power loss; Sliding friction; Hypoid gear; Helical gear

Prakash, AbhinavRendering Secured Connectivity in a Wireless IoT Mesh Network with WPAN's and VANET's
PhD, University of Cincinnati, 2017, Engineering and Applied Science: Computer Science and Engineering
A ubiquitous pervasive network incorporates today’s Internet of Things/Internet of Everything Paradigm: Everything becomes smart with at least one microprocessor and a network interface. All these are under an umbrella of IoT/IoE paradigm where everything is network capable and connected. In most of the cases, these devices have multiple microprocessors and network interfaces at their disposal. In such a scenario, bringing every application to specific network on the same platform is critical, specifically for Sensor Networks, Cloud, WPANs and VANETs. While, enforcing and satisfying the requirements of CIA triad with non-repudiation universally is critical as this can solve multiple existing problems of ISM band exhaustion, leading to excessive collisions and contentions. Cooperative Interoperability also enables universal availability of data across all platforms which can be reliable and fully synchronized. Plug and play universal usability can be delivered. Such a network necessitates robust security and privacy protocols, spanning uniformly across all platforms. Once, reliable data access is made available, it leads to an accurate situation aware decision modeling. Simultaneous multiple channel usage can be exploited to maximize bandwidth otherwise unused. Optimizing Content delivery in hybrid mode which will be the major chunk of network traffic as predicted for near future of IoE. Now, such a proposed hybrid network does sound very complicated and hard to establish and maintain. However, this is the future of networks with huge leaps of technological advancement and ever dropping prices of hardware coupled with immensely improved capabilities, such a hybrid ubiquitous network can be designed and deployed in a realistic scenario. In this work, we go through not only looking into the issues of the large scale hybrid WMN, but also minutely discovering every possible scenario of direct mesh clients or sub-nets (VANET, Cloud or BAN) associated to it. Further, we propose to design and implement a robust all around security and privacy for each and every possible unit of such a large network. Special focus is provided to the application of a BAN in medical usage with intricate details is provided in form of our recent endeavor, along with an ongoing work for a wearable device patent, Smart Shoe (Patent Pending). The concepts explained with this example are equally applicable to any such Wireless Personal Area Networks (WPAN’s).

Committee:

Dharma Agrawal, D.Sc. (Committee Chair); Richard Beck, Ph.D. (Committee Member); Yizong Cheng, Ph.D. (Committee Member); Rashmi Jha, Ph.D. (Committee Member); Wen-Ben Jone, Ph.D. (Committee Member); Marepalli Rao, Ph.D. (Committee Member)

Subjects:

Computer Science

Keywords:

IoT;Mesh Networks;Security;Ubiquitous Networks;Vehicular Networks;Cryptography

Barritt, Brian JamesThe Modeling, Simulation, and Operational Control of Aerospace Communication Networks
Doctor of Philosophy, Case Western Reserve University, 2017, EECS - Computer Engineering
A paradigm shift is taking place in aerospace communications. Traditionally, aerospace systems have relied upon circuit switched communications; geostationary communications satellites act as bent-pipe transponders and are not burdened with packet processing and the complexity of mobility in the network topology. But factors such as growing mission complexity and NewSpace development practices are driving the rapid adoption of packet-based network protocols in aerospace networks. Meanwhile, several new aerospace networks are being designed to provide either low latency, high-resolution imaging or low-latency Internet access while operating in non-geostationary orbits -- or even lower, in the upper atmosphere. The need for high data-rate communications in these networks is simultaneously driving greater reliance on beamforming, directionality, and narrow beamwidths in RF communications and free-space optical communications. This dissertation explores the challenges and offers novel solutions in the modeling, simulation, and operational control of these new aerospace networks. In the concept, design, and development phases of such networks, the dissertation motivates the use of network simulators to model network protocols and network application traffic instead of relying solely on link budget calculations. It also contributes a new approach to network simulation that can integrate with spatial temporal information systems for high-fidelity modeling of time-dynamic geometry, antenna gain patterns, and wireless signal propagation in the physical layer. And towards the operational control of such networks, the dissertation introduces Temporospatial Software Defined Networking (TS-SDN), a new approach that leverages predictability in the propagated motion of platforms and high-fidelity wireless link modeling to build a holistic, predictive view of the accessible network topology and provides SDN applications with the ability to optimize the network topology and routing through the direct expression of network behavior and requirements. This is complemented by enhancements to the southbound interface to support synchronized future enactment of state changes in order to tolerate varying delay and disruption in the control plane. A high-level overview of an implementation of Temporospatial SDN at Alphabet is included. The dissertation also describes and demonstrates the benefits of the application of TS-SDN in Low Earth Orbiting (LEO) satellite constellations and High Altitude Platform Systems (HAPS).

Committee:

Frank Merat (Committee Chair); Rabinovich Michael (Committee Member); Daniel Saab (Committee Member); Mark Allman (Committee Member)

Subjects:

Aerospace Engineering; Computer Engineering; Computer Science

Keywords:

temporospatial; SDN; TS-SDN; aerospace; networks; satellites; LEO; NGSO; constellations; HAPS; high-altitude platforms; STK; wireless; mesh; networking; modeling; simulation; ns-3

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