Conformant planning is a computationally challenging task that generates an action sequence to achieve goal condition with uncertain initial states and non-deterministic actions. The generate-and-complete (in short, GC) approach shows superior performance on conformant planning, which iteratively enumerates the solution of a planning subproblem for a single initial state and attempts to extend it for all initial states until a conform solution is found. However, two major drawbacks of the GC approach hinder its performance: the computational overhead due to state exploration and the insertion of many redundant actions. To overcome the above drawbacks, we improve both verification and completion procedures. Experimental results show that the improved GC planner has significant improvements over the original GC approach in many instances with a large number of initial states. Our approach also outperforms all of state-of-the-art planners, solving 989 instances in comparison to 784, which is the most solved by DNF.

This paper presents the first version of the NIST Cloud Computing Reference Architecture (RA). This is a vendor neutral conceptual model that concentrates on the role and interactions of the identified actors in the cloud computing sphere. Five primary actors were identified - Cloud Service Consumer, Cloud Service Provider, Cloud Broker, Cloud Auditor and Cloud Carrier. Their roles and activities are discussed in this report. A primary goal for generating this model was to give the United States Government (USG) a method for understanding and communicating the components of a cloud computing system for Federal IT executives, Program Managers and IT procurement officials.

For companies and government agencies alike, the emergence of Web services technologies and the evolution of distributed systems toward service oriented architectures (SOA) have helped promote collaboration and information sharing by breaking down "stove-piped" systems and connecting them via loosely coupled, interoperable system-to-system interfaces. Such architectures, however, also bring about their own security challenges that require due consideration. Unfortunately, the current information security mechanisms are insufficient to address these challenges. In particular, the access control models today are mostly static and coarsely grained; they are not well-suited for the service-oriented environments where information access is dynamic and ad-hoc in nature. This paper outlines the access control challenges for Web services and SOA, and proposes an attribute based access control (ABAC) model as a new approach, which is based on subject, object, and environment attributes and supports both mandatory and discretionary access control needs. The paper describes the ABAC model in terms of its authorization architecture and policy formulation, and makes a detailed comparison between ABAC and traditional role-based models, which clearly shows the advantages of ABAC. The paper then describes how this new model can be applied to securing Web service invocations, with an implementation based on standard protocols and open-source tools. The paper concludes with a summary of the ABAC model's benefits and some future directions.

In a traditional time-hopping multiple access ultra-wideband communication system, the orthogonal time-hopping sequence can be designed to improve system performance. However, system capacity is restrictive. We propose a new multiple access system model for a UWB downlink and deploy orthogonal design in three dimensions: time-hopping code, multiuser code, and pulse waveform, or equivalently the position, polarity, and shape of a basic pulse. Such a system provides more freedoms than a traditional time-hopping system. Thus, it is more robust to multiple access interference and can support more users. Performance of the system is analyzed and verified by simulations.