Principled design of the modern Web architecture
The World Wide Web has succeeded in the large part because its software architecture has been designed to meet the needs of an Internet-scale distributed hypermedia system. The modern Web architecture emphasizes scalability of component interactions, generality of interfaces, independent deployment of components, and intermediary components to reduce interaction latency, enforce security, and encapsulate legacy systems. We introduce the Representational State Transfer (REST) architectural style, developed as an abstract model of the Web architecture to guide our redesign and definition of the Hypertext Transfer Protocol and Uniform Resource Identifiers. We describe the software engineering principles guiding REST and the interaction constraints chosen to retain those principles, contrasting them to the constraints of other architectural styles. We then compare the abstract model to the currently deployed Web architecture in order to elicit mismatches between the existing protocols and the applications they are intended to support.

title: Advanced workflow management technologies
abstract: manrand r rackSummary Process, workflow, and groupware projects both in the commercial research worlds have each approached the problem of human communication and dination with different sets of tools and technologies implemented from different pe spectives. Activity dependencies and the philosophical assumptions about how wo performed are managed differently in each discipline. While most of these tools re sent promising approaches, they have yet to be widely adopted, particularly in the of increased usage of online information through the WWW and computer network Electronic information coming to the individual and into the corporation is becomin increasingly unmanageable. People are able to create information regardless of th location or method of access due to increasing mobility and interoperability of the t they use. Because of the common concerns, trends are moving towards overlap an vergence of requirements. However, these communities have yet to identify the uni cross-discipline requirements for a supporting technical infrastructure addressing t level of flexibility, scalability, and support for evolution over time required in these re world settings. This paper surveys the current approaches to project communicatio coordination, details the range of requirements across several related disciplines, identifies various tradeoffs and trends which may effect the adoption, design, and e tion of an advanced technical workflow infrastructure.

title: On the role of software architectures in runtime system reconfiguration
abstract: Society's increasing dependence on software-intensive systems is driving the need for dependable, robust, continuously available systems. Runtime system reconfiguration is one aspect of achieving continuous availability. We present an architecture-based approach to runtime software reconfiguration, highlighting the beneficial role of architectural styles and software connectors in facilitating runtime change. We conclude by describing the implementation of our tool suite, called ArchStudio, that supports runtime reconfiguration using our architecture-based approach.

title: Anomaly Detection in Concurrent Software by Static Data Flow Analysis
abstract: Algorithms are presented for detecting errors and anomalies in programs which use synchronization constructs to implement concurrency. The algorithms employ data flow analysis techniques. First used in compiler object code optimization, the techniques have more recently been used in the detection of variable usage errors in dngle process programs. By adapting these existing algorithms, the sane classes of variable usage errors can be detected in concurrent process programs. Important classes of errors unique to concurrent process programs are also described, and algorithms for their detection are presented.

title: An infrastructure for the rapid development of XML-based architecture description languages
abstract: Research and experimentation in software architectures over the past decade have yielded a plethora of software architecture description languages (ADLs). Continuing innovation indicates that it is reasonable to expect more new ADLs, or at least ADL features. This research process is impeded by the difficulty and cost associated with developing new notations. An architect in need of a unique set of modeling features must either develop a new architecture description language from scratch or undertake the daunting task of modifying an existing language. In either case, it is unavoidable that a significant effort will be expended in building or adapting tools to support the language. To remedy this situation, we have developed an infrastructure for the rapid development of new architecture description languages. Key aspects of the infrastructure are its XML-based modular extension mechanism, its base set of reusable and customizable architectural modeling constructs, and its equally important set of flexible support tools. This paper introduces the infrastructure and demonstrates its value in the context of several real-world applications.

title: Architectural support for trust models in decentralized applications
abstract: Decentralized applications are composed of distributed entities that directly interact with each other and make local autonomous decisions in the absence of a centralized coordinating authority. Such decentralized applications, where entities can join and leave the system at any time, are particularly susceptible to the attacks of malicious entities. Each entity therefore requires protective measures to safeguard itself against these entities. Trust management solutions serve to provide effective protective measures against such malicious attacks. Trust relationships help an entity model and evaluate its confidence in other entities towards securing itself. Trust management is, thus, both an essential and intrinsic ingredient of decentralized applications. However, research in trust management has not focused on how trust models can be composed into a decentralized architecture. The PACE architectural style, described previously [21], provides structured and detailed guidance on the assimilation of trust models into a decentralized entity's architecture. In this paper, we describe our experiments with incorporating four different reputation-based trust models into a decentralized application using the PACE architectural style. Our observations lead us to conclude that PACE not only provides an effective and easy way to integrate trust management into decentralized applications, but also facilitates reuse while supporting different types of trust models. Additionally, PACE serves as a suitable platform to aid the evaluation and comparison of trust models in a fixed setting towards providing a way to choose an appropriate model for the setting.

title: Comparison of conformer distributions in the crystalline state with conformational energies calculated by ab initio techniques
abstract: SummaryThe conformational preferences of 12 molecular substructures in the crystalline state have been determined and compared with those predicted for relevant model compounds by ab initio molecular orbital calculations. Least-squares regression shows that there is a statistically significant correlation between the crystal-structure conformer distributions and the calculated potential-energy differences, even though the calculations relate to a gas-phase environment. Torsion angles associated with high strain energy (>1 kcal mol-1) appear to be very unusual in crystal structures and, in general, high-energy conformers are underrepresented in crystal structures compared with a gas-phase, room-temperature Boltzmann distribution. It is concluded that crystal packing effects rarely have a strong systematic effect on molecular conformations. Therefore, the conformational distribution of a molecular substructure in a series of related crystal structures is likely to be a good guide to the corresponding gas-phase potential energy surface.

title: Authenticating Pollock paintings using fractal geometry
abstract: Jackson Pollock's paintings are currently valued up to US$75M, triggering discussions that attributation procedures featuring subjective visual assessments should be complimented by quantitative scientific procedures. We present a fractal analysis of Pollock's patterns and discuss its potential for authenticity research.

title: Multi-modal Interface for Fluid Dynamics Simulations Using 3-D Localized Sound
abstract: Multi-modal capabilities can be added to a simulation system in order to enhance data comprehension. We describe a system for adding sonification capabilities to a real-time computational fluid dynamics (CFD) simulator. Our system uses Max/MSP modules to add sonic properties to CFD solutions. The enhancements described in this paper allow users to locate sound sources in a 3---D environment using stereo auditory cues to identify data features.

title: A High-Performance Flexible Architecture for Cryptography
abstract: Cryptographic algorithms are more efficiently implemented in custom hardware than in software running on general-purpose processors. However, systems which use hardware implementations have significant drawbacks: they are unable to respond to flaws discovered in the implemented algorithm or to changes in standards. In this paper we show how reconfigurable computing offers high performance yet flexible solutions for cryptographic algorithms. We focus on PipeRench, a reconfigurable fabric that supports implementations which can yield better than custom-hardware performance and yet maintains all the flexibility of software based systems. PipeRench is a pipelined reconfigurable fabric which virtualizes hardware, enabling large circuits to be run on limited physical hardware. We present implementations for Crypton, IDEA, RC6, and Twofish on PipeRench and an extension of PipeRench, PipeRench+. We also describe how various proposed AES algorithms could be implemented on PipeRench. PipeRench achieves speedups of between 2x and 12x over conventional processors.

title: Using Music to Interact with a Virtual Character
abstract: We present a real-time system which allows musicians to interact with synthetic virtual characters as they perform. Using Max/MSP to parameterize keyboard and vocal input, meaningful features (pitch, amplitude, chord information, and vocal timbre) are extracted from live performance in real-time. These extracted musical features are then mapped to character behaviour in such a way that the musician's performance elicits a response from the virtual character. The system uses the ANIMUS framework to generate believable character expressions. Experimental results are presented for simple characters.