Master of Science (M.S.), University of Dayton, 2018, Electrical and Computer Engineering

In this thesis, we propose to develop a secure and distributed network quality-of-experience (QoE) measurement for smart networks. Network measurement capability has been updated gradually as the network technology progresses. For example, software-defined network will enable efficient monitoring and control of the core network. However, end-to-end network QoE measurement requires distributed approaches from the user side. In our proposed measurement framework, a traffic measurement agent is deployed in the last-hop gateway. The gateway is equipped with new features, i.e., encrypted packet classifier, traffic prediction, and user quality-of-service (QoS) to QoE mappings. Since all measurement processes are done at the gateway, end user devices are separated from the entire process. Thus security can be provided by the proposed measurement framework. In addition to the framework, we demonstrate an efficient learning approach to develop the traffic prediction scheme and the QoS to QoE mapping scheme. Experiments results are provided to demonstrate that the developed schemes are applicable to a distributed network QoS measurement framework for smart networks.

Committee: Feng Ye (Advisor); Guru Subramanyam (Committee Member); Eric Balster (Committee Member) Subjects: Electrical Engineering

PhD, University of Cincinnati, 2013, Engineering and Applied Science: Computer Science and Engineering

Multi-hop network has been envisioned to be a key technology in the next generation wireless networks. It offers the most flexible characteristic of the networks, requires no centralized or very small control, and very little configuration, thereby enjoying the quick deployment property. Yet, it has been named as the "next generation" for so many times that its usefulness is being questioned. The difficulty mainly comes from the inferiority in the performance being poor enough to make such networks overshadowed by other type of networks, unless quick deployment is a requirement, or performance is not a major concern. In this dissertation, we investigate the performance issues in multi-hop wireless networks. Some new architectures of multi-hop wireless networks with network coding are thoroughly explored. We first revisit network coding briefly. Being the latest revolution in the wireless world, network coding has evolved into a more practical shape, and has matured to a level so as to be adopted. A general introduction of network coding (network information theory) is covered for better understanding of how this technology would change the computer networks, and why we pick this topic for our research. The first work this dissertation covers is Murco, an opportunistic framework that brings the benefits of both multi-radio multi-channel technology and network coding to the multi-hop wireless networks. This combination, though it seems natural, faces many challenges. We address them with a loose collaboration between network coding and multi-radio technology coordinated by our framework. Our framework requires few changes or compromises on either side, and the simulation results demonstrate enhanced throughput. Following this work, we get into a more complex problem. Coding-aware routing in multi-hop wireless networks is vital for network coding's possible boom. We address this problem with a heuristic routing metric ETOX and a hybrid routing protocol HyCare. (open full item for complete abstract)

Committee: Dharma Agrawal D.Sc. (Committee Chair); Yizong Cheng Ph.D. (Committee Member); Chia Han Ph.D. (Committee Member); Yiming Hu Ph.D. (Committee Member); John Schlipf Ph.D. (Committee Member) Subjects: Computer Science

PhD, University of Cincinnati, 2008, Engineering : Computer Science and Engineering

Currently, Peer-to-Peer overlays can be classified into two main categories: unstructured and structured ones. Unstructured overlays are simple, robust, and powerful in keyword search. Structured ones can scale to very large systems in terms of node number and geography, and guarantee to locate an object within O(Log N) hops. However, both of them face difficulties in efficiency and security of overlays. For unstructured ones, the efficiency problem presented is poor scalability. For structured ones, it is long routing latency and enormous overhead on handling system churn. Moreover, both of them are vulnerable to malicious attacks. Peer-to-Peer overlays belong to application-level network. To a great extension, overlay network designs ignore physical characteristics. As the result, their structures are far from underlying physical network or the distribution pattern of overlay peers. These inconsistencies induce system common operations costly, such as routing and lookup. On the other hand, most peers are assumed to have uniform resources and similar behaviors. Thus, Peer-to-Peer protocols were designed to be symmetric. However, in the realistic environment, peers' resources and behaviors are highly skewed. Symmetric protocols actually compromise system performance. Frequently joining and leaving of peers generates enormous traffic. The significant fraction of peers with high latency/low bandwidth links increase lookup latency. Moreover, under the environment without mutual trust, Peer-to-Peer systems are very vulnerable for varied attacks because they lack a practical authentication mechanism. From a different perspective, this dissertation proposes to construct a highly efficient and secure Peer-to-Peer overlay based on the physical network structure of the Internet and network locality of overlay peers. By naturally integrating different network-aware techniques into the Peer-to-Peer overlay, a novel SNSA (Scalable Network Structure Aware) technique has been dev (open full item for complete abstract)

Committee: Dr. Yiming Hu (Advisor) Subjects: Computer Science

Master of Science, The Ohio State University, 2012, Computer Science and Engineering

For purposes such as end-to-end monitoring, capacity planning, and performance bottleneck troubleshooting across multi-domain networks, there is an increasing trend to deploy interoperable measurement frameworks such as perfSONAR. These deployments expose vast data archives of current and historic measurements, which can be queried using web services. Analysis of these measurements using effective schemes to detect and diagnose anomaly events is vital since it allows for verifying whether network behavior meets expectations. In addition, it allows for proactive notification of bottlenecks that may be affecting large number of users. In this thesis, we describe our novel topology-aware scheme that can be integrated into perfSONAR deployments for detection and diagnosis of network-wide correlated anomaly events. Our scheme involves spatial and temporal analysis on combined topology and uncorrelated anomaly events information for detection of correlated anomaly events. Subsequently, a set of filters are applied on the detected events to prioritize them based on potential bottleneck severity, and to drill-down upon the events nature (e.g., event burstiness) and root-location(s) (e.g., edge or core location affinity). To validate our scheme, we use traceroute information and one-way latency measurements collected over 3 months between various DOE national lab network locations, published via perfSONAR web services. Further, using real-world case studies, we show how our scheme can provide helpful insights for detection and diagnosis of correlated network anomaly events, and can ultimately save time and cost spent on network management.

Committee: Rajiv Ramnath PhD (Advisor); Prasad Calyam PhD (Committee Member); Gagan Agrawal PhD (Committee Member) Subjects: Computer Engineering; Computer Science

Doctor of Philosophy, Case Western Reserve University, 2008, Computer Engineering

In this paper, I develop Directional Antenna Multi-path Location Aware Routing (DA-MLAR) that is a location aware routing with directional antenna capability. DA-MLAR is a reactive routing protocol that minimizes the protocol overhead of other reactive routing protocols. DA-MLAR also improves the packet delivery ratio and end-to-end delay. The long radio transmission range obtained using directional antenna can decrease the number of network partitions there by reducing the number of rebroadcasts. It also reduces the number of routing hops. The directionality further reduces the network interferences by directing the beam only towards the receiving node and involving few intermediate nodes that are in the direction of receiving node. Two extensions of DA-MLAR - DA-MLAR with on demand adjustment of transmission power (DA-MLAR-ODTP) and beam width (DA-MLAR-ODBW) are proposed which further improves the performance metrics of ad hoc networks. In the first phase, the adjustment is made based on the calculated distance between the current sending node and the receiving node in the network. In the second phase, the adjustment also incorporates the effect of random Received Signal Strength (RSS) environment. Multi-objective approach is adopted to assess the network performance of MANET with complex, competing and conflicting objectives – maximizing packet delivery ratio, minimizing protocol overhead, and minimizing energy consumption. The preference of objectives depends on the type of application. In space, energy consumption is given more preference than other objectives. I have used the Normalized Weighted Additive Utility Function (NWAUF) approach to obtain the best alternatives. Through simulations using ns-2, I have demonstrated that DA-MLAR exhibits better network performance. Some performance metrics like packet delivery ratio and end-to-end delay have been significantly improved using DA-MLAR-ODTP and DA-MLAR-ODBW with check in protocol overhead and energy consumpt (open full item for complete abstract)

Committee: Behnam Malakooti (Advisor) Subjects:

MS, University of Cincinnati, 2015, Engineering and Applied Science: Computer Science

Continued evolution of Wireless Body Area Networks (WBANs) has made effective monitoring of vital parameters of a person much faster and efficient, thereby providing better personal healthcare. Sensor nodes of a WBAN acquire critical physiological parameters like heartbeat, neural activity, limb motion, muscle movement and fatigue, temperature, etc. that are monitored by a physician. Important factors in the acceptance of WBAN performance are energy efficiency and the Quality of Service (QoS) supported for such critical data that impact human lives. The sensor nodes of a WBAN are highly constrained in terms of their battery life. Most of the work till date on WBANs uses a star topology which employs single hop communication. This work discusses various factors that affect energy efficiency in a WBAN and establishes the need for a multi-hop tree based topology. It also studies the need for QoS in WBANs and existing support provided by the current Body Area Sensor Network (BASN) Standard. This thesis tackles the all important challenge of providing QoS in autonomous and neighbor-aware multi-hop WBANs in significant detail spread across multiple chapters. In case of independent, autonomous multi-hop WBANs, the aforementioned issue is resolved by implementing a two layer priority-mapping scheme over a reactive Media Access Control (MAC) layer designed to alter durations of the access phases involved as per QoS requirement. In the case of neighbor-aware WBANs, a framework is defined under which a cooperative inter-WBAN routing scheme is implemented through power based weight assignment and fault detection is carried out by employing Kosaraju's two-pass algorithm that discovers the strongly connected components in the network deployment graph.

Committee: Dharma Agrawal D.Sc. (Committee Chair); Raj Bhatnagar Ph.D. (Committee Member); Prabir Bhattacharya Ph.D. (Committee Member) Subjects: Computer Science

Doctor of Philosophy, The Ohio State University, 2013, Computer Science and Engineering

Most of the traditional High End Computing (HEC) applications and current petascale applications are written using the Message Passing Interface (MPI) programming model. Consequently, MPI communication primitives (both point to point and collectives) are extensively used across various scientific and HEC applications. The large-scale HEC systems on which these applications run, by necessity, are designed with multiple layers of switches with different topologies like fat-trees (with different kinds of over-subscription), meshes, torus, etc. Hence, the performance of an MPI library, and in turn the applications, is heavily dependent upon how the MPI library has been designed and optimized to take the system architecture (processor, memory, network interface, and network topology) into account. In addition, parallel jobs are typically submitted to such systems through schedulers (such as PBS and SLURM). Currently, most schedulers do not have the intelligence to allocate compute nodes to MPI tasks based on the underlying topology of the system and the communication requirements of the applications. Thus, the performance and scalability of a parallel application can suffer (even using the best MPI library) if topology-aware scheduling is not employed. Moreover, the placement of logical MPI ranks on a supercomputing system can significantly affect overall application performance. A naive task assignment can result in poor locality of communication. Thus, it is important to design optimal mapping schemes with topology information to improve the overall application performance and scalability. It is also critical for users of High Performance Computing (HPC) installations to clearly understand the impact IB network topology can have on the performance of HPC applications. However, no currently existing tool allows users of such large scale clusters to analyze and to visualize the communication pattern of their MPI based HPC applications in a network topolo (open full item for complete abstract)

Committee: Dhabaleswar Kumar Panda Dr (Advisor); Ponnuswamy Sadayappan Dr (Committee Member); Radu Teodorescu Dr (Committee Member); Karen Tomko Dr (Committee Member) Subjects: Computer Engineering; Computer Science