Tova Roth

Reduction of Visual Complexity in Dynamic Graphs

Graphs are used extensively in software visualization to represent both static aspects of software structure and dynamic aspects of execution-time behavior. However, for realistic subject software systems, there are far too many nodes and edges in the displayed graphs to be comprehensible to an end user. Further, for presentation of dynamics, continual change and redisplay of such large graphs is too demanding for conventional workstation computational resources. This paper poses the problem of “reduction” or “abstraction” in dynamically changing graphs, and proposes a combination of techniques that can be used to reduce the visual complexity of a graph, without obscuring the significant information that it was meant to convey. The abstract graph can be comprehended more readily and it changes far less frequently than the full graph. As well, when the abstract graph does change, it requires far less computation for layout and redisplay. These abstraction techniques are illustrated by way of examples showing their use in systems for visualization of object-oriented and multi-layer software systems.

Weaver: language and runtime for software defined environments

Continuous delivery of software and related infrastructure environments is a challenging proposition. Typical enterprise environments, comprising distributed software and its supporting infrastructure, exhibit non-obvious, often implicit dependencies and requirements. Further increasing this challenge is that knowledge about configuration is fragmented and informally recorded. Given this situation, we propose Weaver, a domain-specific language designed to formally specify blueprints, desired state descriptions of environments. An associated runtime executes blueprints to create or modify environments through a set of target-specific platform providers that supply cloud-specific implementations. New and existing automation to implement and maintain the desired state can be associated with a blueprint specified in Weaver. Furthermore, Weaver supports the definition of conditions to validate a blueprint at design time and deployment time, as well as to continuously validate a deployed environment. We demonstrate the use of Weaver to deploy IBM Connections, an enterprise social software platform.

Graph cutting algorithms for distributed applications partitioning

The problem of optimally allocating the components of a distributed program over several machines can be shown to reduce to a multi-terminal graph cutting problem. In case of three of more terminals, this problem has been shown to be NP-hard. This paper introduces a number of heuristic graph algorithms for use in partitioning distributed object applications --- that is, for deciding which objects should be placed on which machines in order to minimize communication and achieve best overall performance of the application. These heuristics are particularly effective for graphs with characteristics specific to representative distributed object applications.

Partitioning and Assignment of Distributed Object Applications Incorporating Object Replication and Caching

Partitioning of distributed object applications, and task assignment for classical distributed systems, addresses a fundamental problem in client-server and n-tier systems: determining the machine (from high-end servers to tier-0 devices) on which each object should be placed and executed for best overall performance of the application. Traditionally, techniques for automated partitioning have employed a graph-based model of the application being partitioned. In order to remain realistic and effective, these techniques must be extended to incorporate notions of object replication, caching, and synchronization protocols for maintaining consistency.

An algorithm for identifying the abstract syntax of graph-based diagrams

Diagrams play a key role in the information systems domain. However to be meaningful, the diagrams are understood by interpreting visual cues in specific, conventionalized ways, termed conceptual models. One of the major pain points of conceptual models, specified as visual languages, is the inability to capture these visual languages effectively in conventional modeling tools. Instead, conceptual models are drawn using drawing tools and sometimes even by hand. We propose an automatic procedure to derive the syntactic building blocks of graph-based conceptual models. This high-level specification of the visual language can then serve as input for the automatic construction of syntax-aware diagram editors. Our aim is to achieve minimum effort on the part of the users when they eventually work with the graphical editor to produce a new diagram using the proposed syntax.

Dynamic Application Partitioning in VisualAge Generator Version 3.0

This demonstration highlights the technical issues underlying Dynamic Application Partitioning (DAP) in VisualAge Generator Version 3.0.