Convex Hodge Decomposition and Regularization of Image Flows

The total variation (TV) measure is a key concept in the field of variational image analysis. In this paper, we focus on vector-valued data and derive from the Hodge decomposition of image flows a definition of TV regularization for vector-valued data that extends the standard componentwise definition in a natural way. We show that our approach leads to a convex decomposition of arbitrary vector fields, providing a richer decomposition into piecewise harmonic fields rather than piecewise constant ones, and motion texture. Furthermore, our regularizer provides a measure for motion boundaries of piecewise harmonic image flows in the same way, as the TV measure does for contours of scalar-valued piecewise constant images.

Trustworthy clients: Extending TNC to web-based environments

In Trusted Network Connect (TNC), a network access decision is based on the security state of an access requesting party. This mechanism is limited to closed environments such as LANs and VPNs. In this paper, we propose solutions based on authentication standards for enabling TNC in open, web-based scenarios. In particular, an architectural model for TNC is proposed that takes additional security and privacy requirements into account. Furthermore, a communication scheme is proposed that is based on standardised protocols and message formats. This approach provides assurance as to the security state of clients accessing security sensitive web-based services.     

A knowledge-based system for improving the consistency between object models and use case narratives

In today’s systems development environments, object models are playing an increasingly important role in contributing to the agility and flexibility expected of the information systems being built. While current computer-aided software engineering tools can aid in creating object models, they do not provide much support in ensuring that the object models created are consistent with the specifications in use case narratives. This paper presents a methodology and a knowledge-based system to facilitate the verification of consistency of a given object model against a set of use case narratives. The methodology is implemented as a prototype knowledge-based extension to an open source CASE tool. The prototype’s ability to reliably extract relevant information from use case narratives and its role in verifying the consistency of object models have been evaluated using a laboratory experiment. By analyzing use case narratives utilizing natural language processing techniques and applying collaboration patterns and heuristics, this methodology can determine missing and invalid model elements to guide the analyst in creating object models that are consistent with the requirements specified in a set of use case narratives. The results from this design science research indicate that the prototype system can be a useful tool to assist in this process.     

The Myth of Open Web Services: The Rise of the Service Parks

Issues of trust, reliability, and data heterogeneity make it unlikely that we'll have access to a set of free and heterogenous Web services and tools to combine them on the Internet anytime soon. The authors contend, instead, that "service parks" will rise and succeed in the near future as execution environments that support simplified data integration and service reliability. As service park owners establish and leverage branding of their efforts, they will likely build trust within the Web service user community. The most successful service parks will allow users and service providers other than the park owners to to be easily provide and modify services.     

Aligning Business and It: The Process-Driven Architecture Model

Due to the fact that the corporate IT function is tightly coupled to enterprise processes and the organization's information needs, today's IT investments and processes are driven by the same dynamics as the enterprise itself. This article describes a model of a four-layer process-driven architecture (PDA) that can be used as a framework for addressing the alignment of business and IT.     

A Multiphase Dynamic Labeling Model for Variational Recognition-driven Image Segmentation

We propose a variational framework for the integration of multiple competing shape priors into level set based segmentation schemes. By optimizing an appropriate cost functional with respect to both a level set function and a (vector-valued) labeling function, we jointly generate a segmentation (by the level set function) and a recognition-driven partition of the image domain (by the labeling function) which indicates where to enforce certain shape priors. Our framework fundamentally extends previous work on shape priors in level set segmentation by directly addressing the central question of where to apply which prior. It allows for the seamless integration of numerous shape priors such that—while segmenting both multiple known and unknown objects—the level set process may selectively use specific shape knowledge for simultaneously enhancing segmentation and recognizing shape.     

Unique reconstruction of piecewise-smooth images by minimizing strictly convex nonquadratic functionals

We propose the minimization of a nonquadratic functional or, equivalently, a nonlinear diffusion model to smooth noisy image functionsg: R ⁿ R while preserving significant transitions of the data. The model is chosen such that important properties of the conventional quadratic-functional approach still hold: (1) existence of a unique solution continuously depending on the datag and (2) stability of approximations using the standard finite-element method. Relations with other global approaches for the segmentation of image data are discussed. Numerical experiments with real data illustrate this approach.This work was supported by the ESPRIT project SUBSYM.     

Predicting the occurrence and effects of defects in castings

Casting designs are generally based on strength of materials calculations and the experience of the designer. This process leads to incremental development of designs utilizing factors of safety, which lead to increased component weights and inefficient use of materials. In castings, unquantifiable factors (such as shrinkage, porosity, hot tears, and inclusions) lead to conservative design rules. Non-destructive testing does not give the designer a way to assess the effect of indications on part performance. This article describes recent work to predict the occurrence and nature of defects in castings and determine their effect on performance. For more information, contact Christoph Beckermann, University of Iowa, Department of Mechanical and Industrial Engineering, 2412 SC, Iowa City, IA 52242-1527; (319) 335-5681; fax (319) 335-5669; e-mail becker@engineering.uiowa.edu.     

Imaging of Polarons in Ferromagnetic Bilayered Manganites by Scanning Tunnelling Microscopy

We report scanning tunnelling microscopy images of polaronic charge ordered patch on the layered ferromagnet La_2−2x Sr_1+2x Mn₂O₇, x=0.32. The spectroscopic investigation shows that the material is gapped above and below the critical temperature, where the gap changes from 500 to 800 mV, giving evidence for polaronic transport behaviour. This work has been supported by European Project No. 517039 CoMePhS (Controlling Mesoscopic Phase Separation).