Successful software development involves the elicitation, implementation, and management of critical systemic requirements related to qualities such as security, usability, and performance. Unfortunately, even when such qualities are carefully incorporated into the initial design and implemented code, there are no guarantees that they will be consistently maintained throughout the lifetime of the software system. Even though it is well known that system qualities tend to erode as functional and environmental changes are introduced, existing regression testing techniques are primarily designed to test the impact of change upon system functionality rather than to evaluate how it might affect more global qualities. The concept of using goal-centric traceability to establish relationships between a set of strategically placed assessment models and system goals is introduced. This paper describes the process, algorithms, and techniques for utilizing goal models to establish executable traces between goals and assessment models, detect change impact points through the use of automated traceability techniques, propagate impact events, and assess the impact of change upon systemic qualities. The approach is illustrated through two case studies.

IPSec has become the defacto standard protocol for secure Internet communications, providing traffic integrity, confidentiality and authentication. Although IPSec supports a rich set of protection modes and operations, its policy configuration remains a complex and error-prone task. The complex semantics of IP Sec policies that allow for triggering multiple rule actions with different security modes/operations coordinated between different IPSec gateways in the network increases significantly the potential of policy misconfiguration and thereby insecure transmission. Successful deployment of IPSec requires thorough and automated analysis of the policy configuration consistency for IPSec devices across the entire network. In this paper, we present a generic model that captures various filtering policy semantics using Boolean expressions. We use this model to derive a canonical representation for IPSec policies using ordered binary decision diagrams. Based on this representation, we develop a comprehensive framework to classify and identify conflicts that could exist in a single IPSec device (intra-policy conflicts) or between different IPSec devices (inter-policy conflicts) in enterprise networks. Our testing and evaluation study on different network environments demonstrates the effectiveness and efficiency of our approach.

The complexity of languages like Java and C++ can make introductory programming classes in these languages extremely challenging for many students. Part of the complexity comes from the large number of concepts and language features that students are expected to learn while having little time for adequate practice or examples. A second source of difficulty is the emphasis that object-oriented programming places on abstraction. We believe that by placing a larger emphasis on testing in programming assignments in these introductory courses, students have an opportunity for extra practice with the language, and this affords them a gentler transition into the abstract thinking needed for programming. In this paper we describe how we emphasized testing in introductory programming assignments by requiring that students design and implement tests before starting on the program itself. We also provide some preliminary results and student reactions.

This paper focuses on policy languages for (role-based) access control [14, 32], especially in their modern incarnations in the form of trust-management systems [9] and usage control [30, 31]. Any (declarative) approach to access control and trust management has to address the following issues: