Thomas W. Otani

Validating UML Statechart-Based Assertions Libraries for Improved Reliability and Assurance

In this paper we present a new approach for developing libraries of temporal formal specifications. Our approach is novel in its use of UML statechart-based assertions for formal specifications and its emphasis on validation testing, including an emphasis on the inclusion of validation test scenarios as an integral part of a formal specification library. Validation test scenarios are needed to ensure a robust validation process and to improve the reliability and assurance of the specification and resulting software.

Measuring and modeling behavioral decision dynamics in collective evacuation

Identifying and quantifying factors influencing human decision making remains an outstanding challenge, impacting the performance and predictability of social and technological systems. In many cases, system failures are traced to human factors including congestion, overload, miscommunication, and delays. Here we report results of a behavioral network science experiment, targeting decision making in a natural disaster. In a controlled laboratory setting, our results quantify several key factors influencing individual evacuation decision making in a controlled laboratory setting. The experiment includes tensions between broadcast and peer-to-peer information, and contrasts the effects of temporal urgency associated with the imminence of the disaster and the effects of limited shelter capacity for evacuees. Based on empirical measurements of the cumulative rate of evacuations as a function of the instantaneous disaster likelihood, we develop a quantitative model for decision making that captures remarkably well the main features of observed collective behavior across many different scenarios. Moreover, this model captures the sensitivity of individual- and population-level decision behaviors to external pressures, and systematic deviations from the model provide meaningful estimates of variability in the collective response. Identification of robust methods for quantifying human decisions in the face of risk has implications for policy in disasters and other threat scenarios, specifically the development and testing of robust strategies for training and control of evacuations that account for human behavior and network topologies.

Removing the Boundaries: Steps Toward a Cloud Nirvana

In this paper, we present our vision for moving toward an ideal state of cloud computing—a cloud Nirvana. In a cloud Nirvana, boundaries, both physically and artificially created by various types of constraints, imposed on the users would be removed. We propose a three-stage plan toward achieving a cloud computing Nirvana. The three stages are named Migration, Integration, and Unification. Each stage is further divided into steps. We describe how enacting our plan can lead to realizing the benefits of cloud computing.

A design pattern for using non-developmental items in real-time Java

This paper addresses the need to reduce the difficulties in developing time-constrained Java applications. We present a design pattern for a class of time-constrained real-time applications that allows developers to use (and re-use) Java code libraries and non-developmental items (NDI). The proposed design pattern simplifies the implementation of the time-constrained tasks substantially by not requiring the use of no-heap real-time threads. We tested the design pattern with the Java Real-Time System (RTS) 2.0 from the Sun Microsystems. This paper also presents a simple methodology for determining the appropriate values for the RTS run-time parameters (thread priorities, memory usage, process load, and task deadlines) in order to ensure the deterministic execution of the time-constrained tasks.

Cloud Computing for Large-Scale Weapon Systems

Large-scale weapon systems employ distributed computing, but these systems typically do not have a services orientation as found in systems architected to leverage cloud computing. In this paper we describe some of the issues that need to be addressed to enable the application of cloud computing in such systems, using high-level generic use cases and requirements to illustrate the issues. We also discuss how cloud computing can address some of the perplexing problems that arise in the acquisition of large-scale weapon systems as systems of systems, but can also play a role in supporting changes in the workflows employed by the warfighter to attain information superiority within the battlespace.

Putting order into the cloud: Object-oriented UML-based enforcement for document and application organization

In order to improve the ability of users to share data within and across organizations, enterprises can move their data from user-managed devices to data centers accessible via cloud computing services. Such a transition in data storage, access, and management raises technical issues that are not addressed by current operating system, tagging, and configuration and control management technologies. In this paper we describe the notion of a cloud control environment in which cloud services automatically enforce multi-schema-based rules on the organization and manipulation of data objects.

Goal-driven software reuse in the IV&V of system of systems

This paper addresses the need to increase the effectiveness and productivity of independent verification and validation (IV & V) of complex system-of-systems software via software reuse. It builds upon our previous work on reusing the system reference model (SRM) artifacts in the IV & V of system-of-systems software and presents a framework for organizing the reusable artifacts according to a common set of business goals. We demonstrate the proposed framework using NASA science missions as examples.

Computer-assisted validation and verification of cybersecurity requirements

Errors in requirements are often a contributing cause of the failure of critical infrastructure and their underlying information systems to adequately guard against cyber intrusions and withstand cyber attacks. However, detecting errors in the cybersecurity requirements, and for requirements in general, is a challenging task. In this paper we describe how computer-aided formal verification and validation can be leveraged to address the challenge of correctly capturing natural language cybersecurity requirements, converting the natural language statements into formal requirements specifications, and then checking the formal specifications to ensure that they match the original intent of the stakeholders. Our approach centers on creating a one-to-one mapping between natural language requirements and UML statechart assertions. Statechart assertions are Boolean statements about the expected behavior of the system, expressed as UML statecharts. The set of assertions created by the security or software engineer is a formal model of the systems requirements. We demonstrate our approach using examples of formally specifying and validating requirements for correct cyber system behaviors and the detection of illegal business schemes in choreographed web services.

Integrating statechart assertions into Java components using AspectJ

This paper addresses the need for rapid and robust integration of external statechart assertions with the software components of a system of systems (SoSes) for the purpose of runtime verification of the complex SoS behaviors. We describe a framework for connecting assertions to statechart models or to plain Java code using AspectJ. The framework manages connections using a single reusable AspectJ file; designers only need to modify a few lines of source code at the top of the file to link the reusable statechart assertions to a new component. We demonstrate the framework with an example involving a traffic light control system.