UML Assisted Visual Debugging for Distributed Systems

The DOD is developing a Joint Battlespace Infosphere, linking a large number of data sources and user applications. To assist in this process, debugging and analysis tools are required. Software debugging is an extremely difficult cognitive process requiring comprehension of the overall application behavior, along with detailed understanding of specific application components. This is further complicated with distributed systems by the addition of other programs, their large size and synchronization issues. Typical debuggers provide inadequate support for this process, focusing primarily on the details accessible through source code. To overcome this deficiency, this research links the dynamic program execution state to a Unified Modeling Language (UML) class diagram that is reverse-engineered from data accessed within the Java Platform Debug Architecture. This research uses focus + context, graph layout, and color encoding techniques to enhance the standard UML diagram. These techniques organize and present objects and events in a manner that facilitates analysis of system behavior. High-level abstractions commonly used in system design support debugging while maintaining access to low-level details with an interactive display. The user is also able to monitor the control flow through highlighting of the relevant object and method in the display

Visual Debugging of Object-Oriented Systems with the Unified Modeling Language

The Department of Defense (DoD) is developing a Joint Battlespace Infosphere, linking a large number of data sources and user applications. Debugging and analysis tools are required to aid in this process. Debugging of large object-oriented systems is a difficult cognitive process that requires understanding of both the overall and detailed behavior of the application. In addition, many such applications linked through a distributed system add to this complexity. Standard debuggers do not utilize visualization techniques, focusing mainly on information extracted directly from the source code. To overcome this deficiency, this research designs and implements a methodology that enables developers to analyze, troubleshoot and evaluate object-oriented systems using visualization techniques. It uses the standard UML class diagram coupled with visualization features such as focus+context, animation, graph layout, color encoding and filtering techniques to organize and present information in a manner that facilitates greater program and system comprehension. Multiple levels of abstraction, from low-level details such as source code and variable information to high-level structural detail in the form of a UML class diagram are accessible along with views of the program s control flow. The methods applied provide a considerable improvement (up to 1110%) in the number of classes that can be displayed in a set display area while still preserving user context and the semantics of UML, thus maintaining system understanding. Usability tests validated the application in terms of three criteria software visualization, debugging, and general system usability

REDIR: Automated Static Detection of Obfuscated Anti-Debugging Techniques

Reverse Code Engineering (RCE) to detect anti-debugging techniques in software is a very difficult task. Code obfuscation is an anti-debugging technique makes detection even more challenging. The Rule Engine Detection by Intermediate Representation (REDIR) system for automated static detection of obfuscated anti-debugging techniques is a prototype designed to help the RCE analyst improve performance through this tedious task. Three tenets form the REDIR foundation. First, Intermediate Representation (IR) improves the analyzability of binary programs by reducing a large instruction set down to a handful of semantically equivalent statements. Next, an Expert System (ES) rule-engine searches the IR and initiates a sensemaking process for anti-debugging technique detection. Finally, an IR analysis process confirms the presence of an anti-debug technique. The REDIR system is implemented as a debugger plug-in. Within the debugger, REDIR interacts with a program in the disassembly view. Debugger users can instantly highlight anti-debugging techniques and determine if the presence of a debugger will cause a program to take a conditional jump or fall through to the next instruction

Understanding How Reverse Engineers Make Sense of Programs from Assembly Language Representations

This dissertation develops a theory of the conceptual and procedural aspects involved with how reverse engineers make sense of executable programs. Software reverse engineering is a complex set of tasks which require a person to understand the structure and functionality of a program from its assembly language representation, typically without having access to the program\u27s source code. This dissertation describes the reverse engineering process as a type of sensemaking, in which a person combines reasoning and information foraging behaviors to develop a mental model of the program. The structure of knowledge elements used in making sense of executable programs are elicited from a case study, interviews with subject matter experts, and observational studies with software reverse engineers. The results from this research can be used to improve reverse engineering tools, to develop training requirements for reverse engineers, and to develop robust computational models of human comprehension in complex tasks where sensemaking is required

An integrated environment for problem solving and program development

A framework for an integrated problem solving and program development environment that addresses the needs of students learning programming is proposed. Several objectives have been accomplished: defining the tasks required for program development and a literature review to determine the actual difficulties involved in learning those tasks. A comprehensive Study of environments and tools developed to support the learning of problem solving and programming was then performed, covering programming environments, debugging aids, intelligent tutoring systems, and intelligent programming environments. This was followed by a careful analysis and critique of these systems, which uncovered the limitations that have prevented them from accomplishing their goals. Next, an extensive study of problem solving methodologies developed in this century was carried out and a common model for problem solving was produced. The tasks of program development were then integrated with the common model for problem solving. Then, the cognitive activities required for problem solving and program development were identified and also integrated with the common model to form a Dual Common Model for problem Solving and Program Development. This dual common model was then used to define the functional specifications for a problem solving and program development environment which was designed, implemented, tested, and integrated into the curriculum. The development of the new environment for learning problem solving and programming was followed by the planning of a cognitively oriented assessment method and the development of related instruments to evaluate the process and the product of problem solving. A detailed statistical experiment to study the effect of this environment on students\u27 problem solving and program development skills, including system testing by protocol analysis, and performance evaluation of students based on research hypotheses and questions, was also designed, implemented and the result reported

Introductory programming: a systematic literature review

As computing becomes a mainstream discipline embedded in the school curriculum and acts as an enabler for an increasing range of academic disciplines in higher education, the literature on introductory programming is growing. Although there have been several reviews that focus on specific aspects of introductory programming, there has been no broad overview of the literature exploring recent trends across the breadth of introductory programming. This paper is the report of an ITiCSE working group that conducted a systematic review in order to gain an overview of the introductory programming literature. Partitioning the literature into papers addressing the student, teaching, the curriculum, and assessment, we explore trends, highlight advances in knowledge over the past 15 years, and indicate possible directions for future research