14238711
Exploiting style in architectural design environments
As the design of software architectures emerges as a discipline within software engineering, it will become increasingly important to support architectural description and analysis with tools and environments. In this paper we describe a system for developing architectural design environments that exploit architectural styles to guide software architects in producing specific systems. The primary contributions of this research are: (a) a generic object model for representing architectural designs; (b) the characterization of architectural styles as specializations of this object model; and (c) a toolkit for creating an open architectural design environment from a description of a specific architectural style. We use our experience in implementing these concepts to illustrate how style-oriented architectural design raises new challenges for software support environments.
326385
A formal basis for architectural connection
As software systems become more complex, the overall system structure—or software architecture—becomes a central design problem. An important step toward an engineering discipline of software is a formal basis for describing and analyzing these designs. In the article we present a formal approach to one aspect of architectural design: the interactions among components. The key idea is to define architectural connectors as explicit semantic entities. These are specified as a collection of protocols that characterize each of the participant roles in an interaction and how these roles interact. We illustrate how this scheme can be used to define a variety of common architectural connectors. We further provide a formal semantics and show how this leads to a system in which architectural compatibility can be checked in a way analogous to type-checking in programming languages.
11583473
Architectural Mismatch: Why Reuse Is So Hard
Why isn't there more progress toward building systems from existing parts? One answer is that the assumptions of the parts about their intended environment are implicit and either don't match the actual environment or conflict with those of other parts. The authors explore these problems in the context of their own experience with a compositional approach. >
9208543
Formalizing Architectural Connection
As software systems become more complex the overall system structure { or software architecture { becomes a central design problem. An important step towards an engineering discipline of software is a formal basis for describing and analyzing these designs. In this paper we present a theory for one aspect of architectural description: the interactions between components. The key idea is to de ne architectural connectors as explicit semantic entities. These are specied as a collection of protocols that characterize each of the participant roles in an interaction and how these roles interact. We illustrate how this scheme can be used to de ne a variety of common architectural connectors. We provide a formal semantics and show how this leads to a sound deductive system in which architectural compatibility can be checked in a way analogous to type checking in programming languages.
12180900
Towards Formalized Software Architectures
An important goal in software engineering is to describe complex software systems at an architectural level of abstraction. While there are many useful architectural paradigms (pipes, blackboards, etc.) they are typically understood only idiomatically and applied in an ad hoc fashion. We show how a formal model allows us to say precisely what we mean by a software architecture, explore its properties, and systematically describe instances of the architecture. We illustrate the approach using the well-known example of pipe-filter architectures.
7706135
A case study in architectural modeling: the AEGIS system
Software architecture is receiving increasingly attention as a critical design level for software systems. However the current practice of architectural description is largely informal and ad hoc, with the consequence that architectural documents serve as a poor communication mechanism, are difficult to analyze, and may have very little relationship to the implemented system. In an attempt to address these problems several researchers have experimented with formalisms for architectural specification and modelling. One such formalism is the WRIGHT specification language. In this paper, we show how WRIGHT can be used to provide insight into an architectural design by modelling a prototype implementation of part of the AEGIS Weapons System (AWS).
6299292
Automated segmentation of lumbar vertebrae in digital videofluoroscopic images
Low back pain is a significant problem in the industrialized world. Diagnosis of the underlying causes can be extremely difficult. Since mechanical factors often play an important role, it can be helpful to study the motion of the spine. Digital videofluoroscopy has been developed for this study and it can provide image sequences with many frames, but which often suffer due to noise, exacerbated by the very low radiation dosage. Thus, determining vertebra position within the image sequence presents a considerable challenge. There have been many studies on vertebral image extraction, but problems of repeatability, occlusion and out-of-plane motion persist. In this paper, we show how the Hough transform (HT) can be used to solve these problems. Here, Fourier descriptors were used to describe the vertebral body shape. This description was incorporated within our HT algorithm from which we can obtain affine transform parameters, i.e., scale, rotation and center position. The method has been applied to images of a calibration model and to images from two sequences of moving human lumbar spines. The results show promise and potential for object extraction from poor quality images and that models of spinal movement can indeed be derived for clinical application.
17318100
Using an architecture description language for quantitative analysis of real-time systems
An architecture description language (ADL) specifies the structure of an overall system as an assembly of interacting components. ADLs can serve as input to a variety of development tools. We outline the Avionics Architecture Description Language, an emerging SAE standard for describing the architectures of hard real-time, safety-critical embedded computer systems. We describe a suite of tools that perform a set of verification, modeling and analysis, and implementation activities given an AADL specification. We summarize a study that applied these technologies using data about a complex avionics system, identifying and discussing some of the issues raised by this exercise.
44457281
An improved algorithm for relational distance graph matching
One of the problems in computer vision is to give a computer a representation of a scene and recognize the objects in the scene and their spatial relationships. This involves low-level vision (image processing), mid-level vision (feature extraction and measurement) and high-level vision (interpretation). One important part of high-level vision is relational matching, the process of matching two relational descriptions of objects, often for the purpose of object identification. This paper presents an improvement of the original method by Shapiro and Haralick for solving the relational distance graph matching problem for unlabeled graphs on a parallel computer.
11582167
Automated tracking in digitized videofluoroscopy sequences for spine kinematic analysis
Spine kinematic analysis provides useful information to aid understanding of the segmental motion of the vertebrae. Digitized videofluoroscopy (DVF) is the existing practical modality to image spine motion for kinematic data acquisition. However, obtaining kinematic parameters from DVF sequence requires manual landmarking which is a laborious process and can be subjective and error prone. This work develops an automated spine motion tracking algorithm for DVF sequences within a Bayesian framework. By utilizing the anatomical relationships between vertebrae, a dynamic Bayesian network with a particle filter at each node is constructed. The proposed algorithm overcomes the dimensionality problem in a regular particle filter and has more efficient and robust performance. It can provide results of about 1^o and 2pixels (0.2mm) variability in rotation and translation estimation, respectively, during repeated initialization analysis on sequences from simulation and in vivo healthy human subject studies.
8858476
A Parallel Algorithm for Graph Matching and Its MasPar Implementation
Search of discrete spaces is important in combinatorial optimization. Such problems arise in artificial intelligence, computer vision, operations research, and other areas. For realistic problems, the search spaces to be processed are usually huge, necessitating long computation times, pruning heuristics, or massively parallel processing. We present an algorithm that reduces the computation time for graph matching by employing both branch-and-bound pruning of the search tree and massively-parallel search of the as-yet-unpruned portions of the space. Most research on parallel search has assumed that a multiple-instruction-stream/multiple-data-stream (MIMD) parallel computer is available. Since massively parallel stream (SIMD) computers are much less expensive than MIMD systems with equal numbers of processors, the question arises as to whether SIMD systems can efficiently handle state-space search problems. We demonstrate that the answer is yes, and in particular, that graph matching has a natural and efficient implementation on SIMD machines.