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As the functionality that current computer network can provide is becoming complicated, a traditional router with application-specific integrated circuit (ASIC) implementation can't satisfy the flexibility requirements. Instead, a programmable packet forward system based on a general-purpose processor could provide the flexibility. While this system provides flexibility, a new potential security issue arises. Usually, software is involved as the packet forward system is programmable. The software's potential vulnerability, especially as to the remote exploits, becomes an issue of network security. In this thesis work, we proposed a software stack overflow vulnerability on click modular router and show how a disastrous denial-of-service attack on click modular router could be triggered by a single packet. In our research work, click modular router runs on Linux operating system based on general-purpose hardware. We actually showed that even a software router run within a modern operating system's protection is vulnerable by elaborate attack. And we checked the possible stack protection mechanisms on modern OS based on general-purpose hardware and proposed a possible stack protection mechanism for embedded OS.

Accessibility in back-end development is often overlooked, with the majority of discussions and efforts centered on front-end design. To make applications usable for a wider audience, developers must also prioritize incorporating accessibility from the back-end. Back-end web accessibility encompasses the design and development of web-based systems and applications that are accessible to all users, including those with disabilities. This involves optimizing the underlying code and infrastructure for accessibility and implementing features that enable users with disabilities to navigate and interact with the site or application. Ensuring back-end web accessibility is crucial for creating an inclusive online environment accessible to everyone, regardless of their abilities. Presently, there is a significant gap in research regarding back-end accessibility specifics. This study investigates the challenges in implementing back-end accessibility, explores best practices, and aims to facilitate future research on its impact on user experience and system performance.

FPGA-CF is an open-source, portable, extensible communications framework that consists of a small hardware core (less than 600 slices) and a software library/API (Java and C++). It enables a host PC to transmit data at 120 Mb/s to Xilinx-based FPGA boards via Ethernet using standard inter-networking protocols (UDP/IP). A custom lightweight connection-oriented protocol guarantees reliability. The hardware core is directly connected to the Xilinx internal configuration port (ICAP) and supports all ICAP functionality. The core also provides an extensible user-channel interface and provides up to 15, 8-bit user-data channels that can be connected to user circuitry (configurable by the user). The host software API supports both Java and C++ and provides high-level functionality for making connections and transmitting data. The utility of the system is demonstrated by implementing an on-chip test/debug system using FPGA-CF.

This thesis explores the critical role of usability in software development and uses usability heuristics as a cost-effective and efficient method for evaluating various software functions and interfaces. With the proliferation of software development in the modern digital age, developing user-friendly interfaces that meet the needs and preferences of users has become a complex process. Usability heuristics, a set of guidelines based on principles of human-computer interaction, provide a starting point for designers to create intuitive, efficient, and easy-to-use interfaces that provide a seamless user experience. The study uses Jakob Nieson's ten usability heuristics to evaluate the usability of Stack Overflow posts, a popular Q\&A website for developers. Through the analysis of 894 posts related to usability, the study identifies common usability problems faced by users and developers, providing valuable insights into the effectiveness of usability guidelines in software development practice. The research findings emphasize the need for ongoing evaluation and improvement of software interfaces to ensure a seamless user experience. The thesis concludes by highlighting the potential of usability heuristics in guiding the design of user-friendly software interfaces and improving the overall user experience in software development.

The primary research objective of this dissertation is to demonstrate that the effects of communication protocol stack offload (CPSO) on application execution time can be attributed to the following two complementary sources. First, the application-specific computation may be executed concurrently with the asynchronous communication performed by the communication protocol stack offload engine. Second, the protocol stack processing can be accelerated or decelerated by the offload engine. These two types of performance effects can be quantified with the use of the degree of overlapping Do and degree of acceleration Daccs. The composite communication speedup metrics S_comm(Do, Daccs) can be used in order to quantify the combined effects of the protocol stack offload. This dissertation thesis is validated empirically. The degree of overlapping Do, the degree of acceleration Daccs, and the communication speedup Scomm characteristic of the system configurations under test are derived in the course of experiments performed for the system configurations of interest. It is shown that the proposed metrics adequately describe the effects of the protocol stack offload on the application execution time. Additionally, a set of analytical models of the networking subsystem of a PC-based cluster node is developed. As a result of the modeling, the metrics Do, Daccs, and Scomm are obtained. The models are evaluated as to their complexity and precision by comparing the modeling results with the measured values of Do, Daccs, and Scomm. The primary contributions of this dissertation research are as follows. First, the metric Daccs and Scomm are introduced in order to complement the Do metric in its use for evaluation of the effects of optimizations in the networking subsystem on parallel performance in clusters. The metrics are shown to adequately describe CPSO performance effects. Second, a method for assessing performance effects of CPSO scenarios on application performance is developed and presented. Third, a set of analytical models of cluster node networking subsystems with CPSO capability is developed and characterised as to their complexity and precision of the prediction of the Do and Daccs metrics.

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The purpose of this research is to analyze the statics and dynamics of steel smoke stacks subject to excitation by aerodynamic forces. The wind loads experienced by smoke stacks arise from various phenomenon, the most prominent of which are static drag load, vortex shedding, and atmospheric turbulence. The nature of these loading sources around a cylinder are studied in detail. Both static and dynamic loads are capable of producing large tip deflections, and are of the most prominent design criteria for stack designers. A computer program, STACK1, has been created by modifying an existing analysis code, BEAM8, to be used specifically for stack analysis. This analysis code utilizes the transfer matrix method to perform detailed bending and vibration analyses. This new software has been developed to check stack designs for compliance with appropriate steel stack standards, and provide the designer with information regarding the static and dynamic response of the structure. A detailed analysis is performed to demonstrate the validity of approximating a tapered Timoshenko beam with a series of continuous, constant cross-section beams. / Master of Science