Robert Laddaga

Self-Adaptive Software

Repair Plan Concrete Repair Plan Resource Plan Syn the size d S ent ine ls Pla n S truc ture s alerts Development Environment Runtime Environment Figure 1: Dynamic Domain Architecture Approach: Our approach to building adaptive software is based on the notion of a Dynamic Domain Architecture (DDA) (see Figure 1). Dynamic Domain Architectures structure an application domain into layers of common services where each service has a number of variant implementations tailored to different environmental conditions. The architectural level of description also provides ”purpose links” which explain how the components of service

Creating robust software through self-adaptation

OVER THE PAST SEVERAL YEARS, interest has grown considerably in new techniques and technology for improving the task of creating and maintaining high-quality software. These efforts have arisen in response to a growing sense among application developers that traditional approaches are inadequate. Such new methods for improving software efficiency and predictability include intentional programming, evolutionary programming, model-based programming, and self-adaptive software—the last a novel approach sponsored by the Information Technology Office of the US Defense Advanced Research Projects Agency. Software creation, lifetime management, and quality have always been a nearly intractable set of engineering problems. Practitioners have approached these problems with a specific set of engineering techniques, specialized to the software domain: problem and tool abstraction, modularity, testing, and standards, among others. Examples of tool abstraction include high-level languages, operating systems, and database systems; examples of modularity include structured and object-oriented programming. Despite these efforts, and despite significant improvements in software tools and technology, software is still hard to produce, hard to support, and generally of significantly lower quality than we would like. These more traditional approaches have not been worthless in improving our ability to produce better code more affordably. Rather, the problem has been that our reach always exceeds our grasp. As hardware capabilities improve and our understanding of

Virtual mouse vision based interface

A vision-based virtual mouse interface is described that utilizes a robotic head, visual tracking of the users head and hand positions and recognition of user hand signs to control an intelligent kiosk. The user interface supports, among other things, smooth control of the mouse pointer and buttons using hand signs and movements. The algorithms and architecture of real-time vision and robot controller are described.

Introduction: the first international workshop on self-adaptive software

This collection of papers was presented at the international workshop on self adaptive software (IWSAS2000) held at Lady Margaret Hall at the University of Oxford between April 17th and April 19th 2000. They represent the state of the art in a new evolving field of research that attempts to build software systems that are more robust to unpredictable and sometimes hostile environments than we have managed to produce by conventional means.

A location representation for generating descriptive walking directions

An expressive representation for location is an important component in many applications. However, while many location-aware applications can reason about space at the level of coordinates and containment relationships, they have no way to express the semantics that define how a particular space is used. We present Lair, an ontology that addresses this problem by modeling both the geographical relationships between spaces as well as the functional purpose of a given space. We describe how Lair was used to create an application that produces walking directions comparable to those given by a person, and a pilot study that evaluated the quality of these directions. We also describe how Lair can be used to evaluate other intelligent user interfaces.

Introduction to self-adaptive software: applications

The second International Workshop on Self Adaptive Software was held on scenic Lake Balaton, in Hungary during May 17- 19, 2001. The workshop was sponsored by the Technical University of Budapest, and organized by Gabor Peceli, Head of the Department of Measurement and Information Systems, assisted by Simon Gyula, Senior Lecturer in the department. This book presents the collection of papers delivered at this workshop, along with some related papers, and reports of the workshop activities.

Autonomous, Collaborative Control for Resilient Cyber Defense (ACCORD)

ACCORD addresses the need for robust, rapidly adaptive resource allocation mechanisms in cloud computing. It employs a distributed, game-theoretic approach to apportion computational loads in an efficient, prioritized, Pareto-optimal fashion among geographically dispersed cloud computing infrastructure. This paper describes ACCORD algorithms, software implementation, and initial experimental results. Our results illustrate how a distributed, ACCORD-enabled cloud architecture autonomously adapts to the loss of computing resources (e.g., due to failures, poor network connectivity, or cyber attack) while ensuring that users receive maximal, prioritized utility from available cloud resources.

Guest Editors' Introduction: Self-Management through Self-Organization

Given the scale and complexity of todays information systems, its increasingly important that they handle system management problems and tasks themselves--intelligently and autonomously. This special issue focuses on implementing self-management in a variety of distributed systems by observing the self-managing systems that surround us: multicellular organisms, social insects, market economies, human societies, ecosystems, and so on. These systems are made of components that obey local rules and act on the basis of local observations--often selfishly. Yet the system as a whole exhibits global properties such as self-healing, self-tuning, and self-organization. Distilling the key ideas from these systems and incorporating them into information systems often leads to inexpensive, straightforward, and highly robust solutions.This article is part of a special issue on Self-Managing Systems.

Personal Location Agent for Communicating Entities (PLACE)

Traditionally, location systems have been built bottom-up beginning with low-level sensors and adding layers up to high-level context. Consequently, they have focused on a single location-detection technology. With sharing of user location in mind, we created Personal Location Agent for Communicating Entities (PLACE), an infrastructure that incorporates multiple location technologies for the purpose of establishing user location with better coverage, at varying granularities, and with better accuracy. PLACE supports sensor fusion and access control using a common versatile language to describe user locations in a common universe. Its design provides an alternative approach towards location systems and insight into the general problem of sharing user location information.

Model based diagnosis and contexts in self adaptive software

Self Adaptive Software monitors its own operation and attempts to correct deviations from required behavior. In the self adaptive architectures we are developing, it accomplishes this by diagnosing the sources of deviant behavior, whether internal program problems, or contextual changes in an embedded programs environment. The software then responds by reconfiguring itself, to use alternate procedures that either correct the malfunction, or perform better in the current context. We present the GRAVA architecture as an example, and show how it utilizes diagnosis of the external context to limit complexity and enhance robustness in several vision applications.