Modeling collaboration for large-scale software system integration by formal communication models

In the development of large software systems, several synchronization points have to be passed successfully in order to achieve high-end user acceptance of the final system. In particular, the integration of conceptual design entities has turned out to be the most crucial step in software development. At this point, an explicit representation of the organizational knowledge, namely how the integration can be performed, is required. The overall organization of the integration of design entities is a set of knowledge, action (including communication), and time. The knowledge part comprises the integration procedure itself as well as the design entities. Actions are performed by the members of the project team (project leaders, developers). Each integration step has to be performed synchronized, so that each member of the development team knows concurrently the status of the integration procedure. All other individual design activities are usually performed asynchronously. According to the need for an explicit representation of the organizational knowledge for large software system design, this paper attempts tounderstand the nature of large software system integration and formallydescribes the coordination of a dispersed set of software developers. The organizational knowledge is represented by processes that occur in an asynchronous development environment. The design knowledge is assigned to logical formulas that are processed as exchanged messages among developers. Hence, the activities for integration are based on the transmission of messages. Time-critical events, such as the integration of a particular design entity into the final conceptual design of the software system, have to become common knowledge concurrently for all developers. This organizational constraint has been formalized in the communication model. Not only can the proposed framework be adapted to organizational changes in a flexible way, it can also be applied to any specific development strategy for the integration of conceptual design entities. Thus, such kind of formal communication models may provide a sound basis for cooperative CASE (computer-aided software engineering) tools.This work has been sponsored by the Max Kade Foundation, New York.     

Shifting knowledge from analysis to design: requirements for contextual user interface development

There is consensus among the members of the HCI community as well as among software developers that work tasks and user characteristics (i.e. context) should play a leading role in the course of system development. There seems to be less consensus on how the information about users and work tasks should be acquired and subsequently moved to the design process of a development project. Due to the use of unifying methods and concepts--such as object-orientation-- that might be used for analysis, design and implementation, this transition seems to be facilitated. However, few inputs have been provided to guide developers on how to shift knowledge from analysis to design when task- and user knowledge are considered to be inherent parts of the development knowledge. This paper details the interface between analysis and design, reviews existing concepts to bridge the gap between the two phases of development, and enriches these findings with some empirical results from a survey with respect to practical experiences. From these findings, requirements to successfully shift knowledge in the early phases of software development have been derived.     

User diversity and design representation: Towards increased effectiveness in Design for All

This paper addresses user modelling for “Design for All” in a model-based approach to Human-Computer Interaction, paying particular attention to placing user models within organisational role- and task-related contexts. After reviewing a variety of user modelling approaches, and deriving requirements for user modelling related to Design for All, the paper proposes a role-driven individualised approach. Such an approach is based on a model-based representation schema and a unifying notation that keeps the user’s models and the contextual information transparent and consistent. Individualisation is achieved by coupling symbolic model specifications with neural networking on synchronisation links between symbolic representation elements. As a result, user modelling for Design for All is achieved not by stereotypical user properties and functional roles, but by accommodating the actual users’ behaviour. Published online: 18 May 2001     

TADEUS: seamless development of task-based and user-orientedinterfaces

Task-based and user-oriented user interfaces utilize knowledge about user tasks and user characteristics to the utmost extent. They support users throughout their work flows, and must be constructed by a development process that avoids loss of application context and involves user feedback, from requirements specification to code generation. The concepts behind the task analysis/design/end users systems (TADEUS) approach to enable seamless task-based development are a semantically rich representation scheme, a model-driven development procedure, a diagrammatic notation and unifying specification scheme. Thus, interactive applications can be developed seamlessly. Specifications comprise problem domain knowledge, work processes, user roles and personal profiles, as well as interaction modalities (required for task accomplishment). For user-interface prototyping the TADEUS environment contains a model interpreter that executes structure and behavior specifications. This way, early feedback on task-based portals can be provided by users. In this paper we detail the latest developments in the TADEUS project when implementing a work-process based usability life cycle. We review the underlying methodology and the features of the TADEUS environment, in order to demonstrate the benefits for developers and users resulting of smooth transition support for and between the different stages of development     

What is the tensile strength of a ceramic to be used in numerical models for predicting crack initiation?

Criteria for predicting initiation of cracks in brittle materials like ceramics are based on two parameters: the material fracture toughness and the tensile strength. Standardized experiments exist to estimate the former. However, the tensile strength is often taken from experiments (mainly uniaxial bending) on specimens with various geometries and surface finish, usually tested under ambient conditions at a given loading rate. The reported strength is commonly the Weibull characteristic strength, which scatters due to the critical defect size distribution on the tested specimen. In this work, we propose a definition of the “inherent” or “intrinsic” tensile strength to be used in numerical models, making a distinction between extrinsic defects due to manufacturing and intrinsic ones relying on the microstructure. Our approach is based on the Finite Fracture Mechanics theory and the Coupled Criterion applied to small surface flaws and its influence on the measured (extrinsic) strength. Numerical results are compared with experiments on alumina reported in the literature. In addition, a model for the Petch law (strength vs. grain size) in polycrystalline materials is proposed using the Coupled Criterion, which predicts an initial crack length of increasing numbers of grains as the grain size decreases.     

Enterprise modelling for interoperable and knowledge-based enterprises

The paper first takes a look at the state of the art on the overlapping areas of: Enterprise Modelling, Enterprise Integration/Interoperability, Organisational Learning and Knowledge Management. We identify requirements, characterisation and recent contributions for the interoperable and knowledge-based enterprises in the area of production of goods or services. It is then advocated that Enterprise Modelling and Knowledge Representation should combine their efforts to develop reference and reusable core manufacturing enterprise ontologies to support Enterprise Integration and Interoperability on one hand and open the door to Organisational Learning and management of active knowledge for the ‘smart’ enterprises of tomorrow on the other hand. This is illustrated by case studies from projects carried out in industry.     

DNA polymorphism, allogenic bone marrow transplantation and peripheral cell chimerism

BACKGROUND: Bone marrow transplantation or transplantation of peripheral stem cells is an effective treatment of a number of diseases. Its increasing success and expanding use in associated with the development of molecular diagnostic methods which enable to follow up the graft from its engraftment in a recipient and then during the whole posttransplantation period at the level extremely small numbers of cells. METHODS AND RESULTS: In peripheral blood of patients, genotypes of the following loci were examined by polymerase chain reaction (PCR): APOB, COL2A1, D17S20, D1S80, HVR/1G, SRY and AMXY. Technique of restriction analysis was used for loci DXYS20 and DXYS75. 1. The first signs of donor bone marrow activity were observed in 50% of patients already at the beginning of the second week after transplantation, while in the second half of patients increasing number of donor cells in peripheral blood was noticed in the second and third week. 2. Engraftment with full and permanent substitution of own bone marrow without presence of recipients cells in peripheral blood--complete chimerism--was achieved only in a part of patients (cca 50%). 3. Peripheral blood of other patients did not contain only donor cells but also recipients cells--mixed chimerism. With regard to its onset, the authors have divided mixed chimerism into early and late, taking into account that some patients can develop both types. In patients under study, early chimerism was found more frequently, which apparently resulted from a shorter period of observation of lately transplanted patients. 4. In cases of oncohaematologic patients, which allowed to study specifically the presence of a pathologic clone, the follow-up of chimerism enabled to distinguish between relapse of the original disease and "biologic" recovery--resurrection of original disease-free haematopoiesis. 5. Regression of mixed chimerism was supposed to be the result of treatment focused at the original disease (CML), in some patients, however, it was a spontaneous process. CONCLUSIONS: Follow-up of cellular chimerism in transplanted patients by means of molecular genetic methods provides substantial information about patient's shape which can be utilized it is necessary to decide on treatment procedures. For this reason it is desirable that examination of chimerism by molecular methods should form integral part of care of these patients.     

Two numerical models for landslide dynamic analysis

Two microcomputer-based numerical models (Dynamic ANalysis (DAN) and three-dimensional model DAN (DAN3D)) have been developed and extensively used for analysis of landslide runout, specifically for the purposes of practical landslide hazard and risk assessment. The theoretical basis of both models is a system of depth-averaged governing equations derived from the principles of continuum mechanics. Original features developed specifically during this work include: an open rheological kernel; explicit use of tangential strain to determine the tangential stress state within the flowing sheet, which is both more realistic and beneficial to the stability of the model; orientation of principal tangential stresses parallel with the direction of motion; inclusion of the centripetal forces corresponding to the true curvature of the path in the motion direction and; the use of very simple and highly efficient free surface interpolation methods. Both models yield similar results when applied to the same sets of input data.Both algorithms are designed to work within the semi-empirical framework of the “equivalent fluid” approach. This approach requires selection of material rheology and calibration of input parameters through back-analysis of real events. Although approximate, it facilitates simple and efficient operation while accounting for the most important characteristics of extremely rapid landslides. The two models have been verified against several controlled laboratory experiments with known physical basis. A large number of back-analyses of real landslides of various types have also been carried out. One example is presented. Calibration patterns are emerging, which give a promise of predictive capability.     

Ocular Graft-versus-Host Disease in a Chemotherapy-Based Minor-Mismatch Mouse Model Features Corneal (Lymph-) Angiogenesis

Ocular graft-versus-host disease (oGVHD) is a fast progressing, autoimmunological disease following hematopoietic stem cell transplantation, leading to severe inflammation of the eye and destruction of the lacrimal functional unit with consecutive sight-threatening consequences. The therapeutic “window of opportunity” is narrow, and current treatment options are limited and often insufficient. To achieve new insights into the pathogenesis and to develop new therapeutic approaches, clinically relevant models of oGVHD are desirable. In this study, the ocular phenotype was described in a murine, chemotherapy-based, minor-mismatch GVHD model mimicking early-onset chronic oGVHD, with corneal epitheliopathy, inflammation of the lacrimal glands, and blepharitis. Additionally, corneal lymphangiogenesis was observed as part of oGVHD pathogenesis for the first time, thus opening up the investigation of lymphangiogenesis as a potential therapeutic and diagnostic tool.