Digital systems are pervasive in modern societies -- augmenting personal and commercial driving, detecting cancer, and exploiting transitory events in financial markets. Attacks on these systems are growing in number, sophistication, and impact. Current cyber defenses are proving inadequate against some of these attacks. Cyber defense tools that…

Motivated by applications in health care systems, this study focused on queueing network models with instances of simultaneous resource possession under capacity restrictions in different stages. Customers during service at certain nodes in the first-level or primary system may simultaneously need service from a second-level server. In this…

Internet of Things ("IoT") systems are complex, asynchronous solutions often comprised of various software and hardware components developed in isolation of each other. These components function with different degrees of reliability and performance over an inherently unreliable network, the Internet. Many IoT systems are developed within…

Encryption based ransomware operates by iterating through all files with specific extensions on the computer and mutating them into an unusable form. The mutation, in many cases, can only be reversed if the user pays the operator of the ransomware a fee to get their files back. K-12 school districts have fallen victim to rampant malware as a…

Video compression and communication has been an important field over the past decades and critical for many applications, e.g., video on demand, video-conferencing, and remote education. In many applications, providing low-delay and error-resilient video transmission and increasing the coding efficiency are two major challenges. Low-delay and…

This thesis identifies three essays which contribute to the foundational understanding of the vulnerabilities and risk towards potentially implementing wireless grid Edgeware technology in a virtualized cloud environment. Since communication networks and devices are subject to becoming the target of exploitation by hackers (e.g. individuals who…

Despite the recent advances in systems and network security, attacks on large enterprise networks consistently impose serious challenges to maintaining data privacy and software service integrity. We identify two main problems that contribute to increasing the security risk in a networked environment: (i) vulnerable servers, workstations, and…

Use of the Patch Vulnerability Management (PVM) process should be seriously considered for any networked computing system. The PVM process prevents the operating system (OS) and software applications from being attacked due to security vulnerabilities, which lead to system failures and critical data leakage. The purpose of this research is to…

Efficient self-organizing virtual clusterheads that supervise data collection based on their wireless connectivity, risk, and overhead costs, are an important element of Wireless Sensor Networks (WSNs). This function is especially critical during deployment when system resources are allocated to a subsequent application. In the presented research,…

This dissertation explores the social worlds of pirated software discs and free/open source software in Vietnam to describe the practices of copying, evangelizing, and translation. This dissertation also reveals the cultural logics of similarity and continuity that sustain these social worlds. Taken together, this dissertation argues that the…

Much of our critical infrastructure is controlled by large software systems whose participants are distributed across the Internet. As our dependence on these critical systems continues to grow, it becomes increasingly important that they meet strict availability and performance requirements, even in the face of malicious attacks, including those…

Opportunities in education are lacking in many parts of the developed nations and are missing in most parts of the developing nations. This is, in significant part, due to shortages of classroom instructional resources such as quality teaching staff, hardware and software. Distance education (DE) has proved to be a successful teaching approach and…

Improvements in Information Technology (IT) infrastructure and standardization of interoperability standards among heterogeneous Information System (IS) applications have brought a paradigm shift in the way an IS application could be used and delivered. Not only an IS application can be built using standardized component but also parts of it can…

In current Peer-to-Peer networks, distributed and semantic free indexing is widely used by systems adopting "Distributed Hash Table" ("DHT") mechanisms. Although such systems typically solve a. user query rather fast in a deterministic way, they only support a very narrow search scheme, namely the exact hash key match. Furthermore, DHT systems put…

This dissertation deals with a multiterminal source model for secret key generation by multiple network terminals with prior and privileged access to a set of correlated signals complemented by public discussion among themselves. Emphasis is placed on a characterization of secret key capacity, i.e., the largest rate of an achievable secret key,…