Change decision support:extraction and analysis of late architecture changes using change characterization and software metrics

Software maintenance is one of the most crucial aspects of software development. Software engineering researchers must develop practical solutions to handle the challenges presented in maintaining mature software systems. Research that addresses practical means of mitigating the risks involved when changing software, reducing the complexity of mature software systems, and eliminating the introduction of preventable bugs is paramount to today’s software engineering discipline. Giving software developers the information that they need to make quality decisions about changes that will negatively affect their software systems is a key aspect to mitigating those risks. This dissertation presents work performed to assist developers to collect and process data that plays a role in change decision-making during the maintenance phase. To address these problems, developers need a way to better understand the effects of a change prior to making the change. This research addresses the problems associated with increasing architectural complexity caused by software change using a twoold approach. The first approach is to characterize software changes to assess their architectural impact prior to their implementation. The second approach is to identify a set of architecture metrics that correlate to system quality and maintainability and to use these metrics to determine the level of difficulty involved in making a change. The two approaches have been combined and the results presented provide developers with a beneficial analysis framework that offers insight into the change process

Making intelligent systems team players: Case studies and design issues. Volume 1: Human-computer interaction design

Initial results are reported from a multi-year, interdisciplinary effort to provide guidance and assistance for designers of intelligent systems and their user interfaces. The objective is to achieve more effective human-computer interaction (HCI) for systems with real time fault management capabilities. Intelligent fault management systems within the NASA were evaluated for insight into the design of systems with complex HCI. Preliminary results include: (1) a description of real time fault management in aerospace domains; (2) recommendations and examples for improving intelligent systems design and user interface design; (3) identification of issues requiring further research; and (4) recommendations for a development methodology integrating HCI design into intelligent system design

Mission Dependency Index of Air Force Built Infrastructure: Knowledge Discovery with Machine Learning

Mission Dependency Index (MDI) is a metric developed to capture the relative criticality of infrastructure assets with respect to organizational missions. The USAF adapted the MDI metric from the United States Navy’s MDI methodology. Unlike the Navy’s MDI data collection process, the USAF adaptation of the MDI metric employs generic facility category codes (CATCODEs) to assign MDI values. This practice introduces uncertainty into the MDI assignment process with respect to specific missions and specific infrastructure assets. The uncertainty associated with USAF MDI values necessitated the MDI adjudication process. The MDI adjudication process provides a mechanism for installation civil engineer personnel to lobby for accurate MDI values for specific infrastructure assets. The MDI adjudication process requires manual identification of MDI discrepancies, documentation, and extensive coordination between organizations. Given the existing uncertainty with USAF MDI values and the effort required for the MDI adjudication process, this research pursues machine learning and the knowledge discovery in databases (KDD) process to identify and understand relationships between real property data and mission critical infrastructure. Furthermore, a decision support tool is developed for the MDI adjudication process. Specifically, supervised learning techniques are employed to develop a classifier that can identify potential MDI discrepancies. This automation effort serves to minimize the manual MDI review process by identifying a subset of facilities for potential adjudication

Survivability modeling for cyber-physical systems subject to data corruption

Cyber-physical critical infrastructures are created when traditional physical infrastructure is supplemented with advanced monitoring, control, computing, and communication capability. More intelligent decision support and improved efficacy, dependability, and security are expected. Quantitative models and evaluation methods are required for determining the extent to which a cyber-physical infrastructure improves on its physical predecessors. It is essential that these models reflect both cyber and physical aspects of operation and failure. In this dissertation, we propose quantitative models for dependability attributes, in particular, survivability, of cyber-physical systems. Any malfunction or security breach, whether cyber or physical, that causes the system operation to depart from specifications will affect these dependability attributes. Our focus is on data corruption, which compromises decision support -- the fundamental role played by cyber infrastructure. The first research contribution of this work is a Petri net model for information exchange in cyber-physical systems, which facilitates i) evaluation of the extent of data corruption at a given time, and ii) illuminates the service degradation caused by propagation of corrupt data through the cyber infrastructure. In the second research contribution, we propose metrics and an evaluation method for survivability, which captures the extent of functionality retained by a system after a disruptive event. We illustrate the application of our methods through case studies on smart grids, intelligent water distribution networks, and intelligent transportation systems. Data, cyber infrastructure, and intelligent control are part and parcel of nearly every critical infrastructure that underpins daily life in developed countries. Our work provides means for quantifying and predicting the service degradation caused when cyber infrastructure fails to serve its intended purpose. It can also serve as the foundation for efforts to fortify critical systems and mitigate inevitable failures --Abstract, page iii

Army-NASA aircrew/aircraft integration program (A3I) software detailed design document, phase 3

The capabilities and design approach of the MIDAS (Man-machine Integration Design and Analysis System) computer-aided engineering (CAE) workstation under development by the Army-NASA Aircrew/Aircraft Integration Program is detailed. This workstation uses graphic, symbolic, and numeric prototyping tools and human performance models as part of an integrated design/analysis environment for crewstation human engineering. Developed incrementally, the requirements and design for Phase 3 (Dec. 1987 to Jun. 1989) are described. Software tools/models developed or significantly modified during this phase included: an interactive 3-D graphic cockpit design editor; multiple-perspective graphic views to observe simulation scenarios; symbolic methods to model the mission decomposition, equipment functions, pilot tasking and loading, as well as control the simulation; a 3-D dynamic anthropometric model; an intermachine communications package; and a training assessment component. These components were successfully used during Phase 3 to demonstrate the complex interactions and human engineering findings involved with a proposed cockpit communications design change in a simulated AH-64A Apache helicopter/mission that maps to empirical data from a similar study and AH-1 Cobra flight test

Challenges in Complex Systems Science

FuturICT foundations are social science, complex systems science, and ICT. The main concerns and challenges in the science of complex systems in the context of FuturICT are laid out in this paper with special emphasis on the Complex Systems route to Social Sciences. This include complex systems having: many heterogeneous interacting parts; multiple scales; complicated transition laws; unexpected or unpredicted emergence; sensitive dependence on initial conditions; path-dependent dynamics; networked hierarchical connectivities; interaction of autonomous agents; self-organisation; non-equilibrium dynamics; combinatorial explosion; adaptivity to changing environments; co-evolving subsystems; ill-defined boundaries; and multilevel dynamics. In this context, science is seen as the process of abstracting the dynamics of systems from data. This presents many challenges including: data gathering by large-scale experiment, participatory sensing and social computation, managing huge distributed dynamic and heterogeneous databases; moving from data to dynamical models, going beyond correlations to cause-effect relationships, understanding the relationship between simple and comprehensive models with appropriate choices of variables, ensemble modeling and data assimilation, modeling systems of systems of systems with many levels between micro and macro; and formulating new approaches to prediction, forecasting, and risk, especially in systems that can reflect on and change their behaviour in response to predictions, and systems whose apparently predictable behaviour is disrupted by apparently unpredictable rare or extreme events. These challenges are part of the FuturICT agenda

Modeling Cyber Situational Awareness through Data Fusion

Cyber attacks are compromising networks faster than administrators can respond. Network defenders are unable to become oriented with these attacks, determine the potential impacts, and assess the damages in a timely manner. Since the observations of network sensors are normally disjointed, analysis of the data is overwhelming and time is not spent efficiently. Automation in defending cyber networks requires a level of reasoning for adequate response. Current automated systems are mostly limited to scripted responses. Better defense tools are required. This research develops a framework that aggregates data from heterogeneous network sensors. The collected data is correlated into a single model that is easily interpreted by decision-making entities. This research proposes and tests an impact rating system that estimates the feasibility of an attack and its potential level of impact against the targeted network host as well the other hosts that reside on the network. The impact assessments would allow decision makers to prioritize attacks in real-time and attempt to mitigate the attacks in order of their estimated impact to the network. The ultimate goal of this system is to provide computer network defense tools the situational awareness required to make the right decisions to mitigate cyber attacks in real-time

APPROACHES TO VULNERABILITY ANALYSIS FOR DISCOVERING THE CRITICAL ROUTES IN ROADWAY NETWORKS

All modes of transportation are vulnerable to disruptions caused by natural disasters and/or man-made events (e.g., accidents), which may have temporary or permanent consequences. Identifying crucial links where failure could have significant effects is an important component of transportation network vulnerability assessments, and the risk of such occurrences cannot be underestimated. The ability to recognize critical segments in a transportation network is essential for designing resilient networks and improving traffic conditions in scenarios like link failures, which can result in partial or full capacity reductions in the system. This study proposes two approaches for identifying critical links for both single and multiple link disruptions. New hybrid link ranking measures are proposed, and their accuracy is compared with the existing traffic-based measures. These new ranking measures integrate aspects of traffic equilibrium and network topology. The numerical study revealed that three of the proposed measures generate valid findings while consuming much less computational power and time than full-scan analysis measures. To cover various disruption possibilities other than single link failure, an optimization model based on a game theory framework and a heuristic algorithm to solve the mathematical formulation is described in the second part of this research. The proposed methodology is able to identify critical sets of links under different disruption scenarios including major and minor interruptions, non-intelligent and intelligent attackers, and the effect of presenting defender. Results were evaluated with both full scan analysis techniques and hybrid ranking measures, and the comparison demonstrated that the proposed model and algorithm are reliable at identifying critical sets of links for random and specially targeted attacks based on the adversary\u27s link selection in both partial and complete link closure scenarios, while significantly reducing computational complexity. The findings indicate that identifying critical sets of links is highly dependent on the adversary\u27s inelegancy, the presence of defenders, and the disruption scenario. Furthermore, this research indicates that in disruptions of multiple links, there is a complex correlation between critical links and simply combining the most critical single links significantly underestimates the network\u27s vulnerability

THE CLASSROOM AS INQUIRY LEARNING COMMUNITY: A PRACTITIONER STUDY OF ADOLESCENTS’ DEVELOPING CRITICAL LITERACIES

This dissertation presents findings from 10 months of practitioner inquiry (Cochran-Smith & Lytle, 1993, 2009) using qualitative data collection and analysis. Informed by communities of practice theory (Lave & Wenger, 1991) and critical literacy theory (Luke, 2000; Janks, 2010; Comber, 2016), the study asked the following research questions: 1) What characterizes a classroom learning community designed to support adolescents\u27 experiences with inquiry learning? 2) In what ways do adolescents practice critical literacies when engaged with inquiry learning? and, 3) What roles do teachers navigate when working with adolescents developing critical literacies through inquiry learning? The study took place in an elective course co-designed by an English teacher and a librarian to support 12th grade students in developing their research skills. Data sources included semi-structured interviews, weekly memos, teaching artifacts and student work samples, emails, text messages, photos, and videos. Analysis and writing were informed by narrative inquiry (Schaafsma & Vinz, 2011). Findings demonstrated that students experienced various levels of confluence in developing their inquiry literacies and critical literacies when engaged in work designed to address both skill sets. Findings suggest implications for members of school communities working to develop opportunities in the curriculum for inquiry learning and critical literacy, for teacher researchers designing future practitioner inquiry research projects, and for teacher educators working with pre-service English teachers