Improving Context Interpretation by Using Fuzzy Policies: The Case of Adaptive Video Streaming

Best paper awardInternational audienceAdaptation is an increasingly important requirement for software systems executing in large-scale, heterogeneous, and dynamic environments. A central aspect of the adaptation methodology is management of contextual information needed to support the adaptation process. A major design challenge of managing contextual data lies in the fact that the information is partial, uncertain, and inherently suitable for diverging interpretations. While existing adaptation solutions focus on techniques, methods, and tools, the challenge of managing and interpreting ambiguous contextual information remains largely unresolved. In this paper we present a new adaptation approach that aims to overcome these issues by applying fuzzy set theory and approximate reasoning. We have defined a knowledge management scheme that allows the interpretation of imprecise information and effectively integrated it into the adaptation feedback control loop. To test and evaluate our solution, we implemented it in an adaptation engine to perform rate control for media streaming applications. We show the benefits of our approach in terms of flexibility and performance when compared to more traditional methods, such as TCP-friendly rate control

Contextual Adaptation. Human Functioning as Dynamic Interaction: A Social Work Perspective

Despite the recent development of theories in the social sciences that define human development and functioning in an integrated, nuanced and complex manner, the social work concept of “person-in-environment” remains outdated and limited. This is in part due to the “person” and “environment”--the biological, psychological, and social environments--being defined in distinction from one another. In order to remain current and effective in arguing on behalf of a clear professional voice in the field, social workers must not only engender but also promote a fundamental practice perspective that addresses complexity. A reformulation of “person-in-environment” can help social workers more fully realize the desire to unite under the common professional mandates requiring that both a “person-in-environment” perspective and a full biopsychosocial picture be taken into clinical accounts. To meet this aim I develop the concept of contextual adaptation, a new definition of “person-in-environment” reliant on tenets of nonlinear dynamic systems theory, specifically chaos theory. Nonlinear dynamic systems theory offers a unique opportunity for social workers to retain the core potentiality and utility of “person-in-environment,” that which enables them to account for the importance of environment, but reformulate it so as to create a more viable concept. Contextual adaptation is defined as a biopsychosocial process allowing for an integrated focus on the influence and management of the overlapping contexts of self, interpersonal experience, and sociocultural demands. Human development and functioning are established as a spectrum of adaptive behavior based on the regulation of the needs and requirements of internal processes, relational experience, and external influence

Strategic fit: microfoundations of firm’s environmental performance

© 2019, Emerald Publishing Limited. Purpose: Strategic fit is known to be an important antecedent to a firm’s performance, but there is little research explaining its influence on firm’s environmental performance. This paper aims to propose that strategic fit is likely to affect two firm-level outcomes: dynamic equilibrium and dynamic disequilibrium. Design/methodology/approach: Prior debate has underlined the role of adaptation vs selection in achieving strategic fit, but we assert that firms vary in their strategic fit. This paper models inter-firm differentials in environmental performance, using survey data from a sample of Chinese small and medium enterprises. Findings: Transformative leadership, operational agility and knowledge-based identity facilitate compensatory fit, while productivity growth, strategic adaptability and low product-market maturity enable strategic fit. Theoretical implications: The authors show how low strategic fit may provide selection advantages via compensatory fit. Some firms do seek to achieve greater fit to the embedded contextual contingencies (dynamic equilibrium) at the cost of their energy. However, others respond to the expectations for green performance that are presently orthogonal to the embedded context to realize compensatory fit using the energy of the context (dynamic disequilibrium). This manifests as differential capabilities for adaptation vs selection. Practical implications: The findings highlight how the firms may use cultural fit pathway for transcending the phenomenological tradeoffs between economic performance-oriented strategic fit and ecological performance-oriented compensatory fit. Originality/value: This paper shows how low strategic fit may provide selection advantages via compensatory fit. Some firms do seek to achieve greater fit to the embedded contextual contingencies (dynamic equilibrium) at the cost of their energy. However, others respond to the expectations for green performance that are presently orthogonal to the embedded context, to realize compensatory fit using the energy of the context (dynamic disequilibrium). This manifests as differential capabilities for adaptation vs selection

Neural Tuning Functions Underlie Both Generalization and Interference

In sports, the role of backswing is considered critical for generating a good shot, even though it plays no direct role in hitting the ball. We recently demonstrated the scientific basis of this phenomenon by showing that immediate past movement affects the learning and recall of motor memories. This effect occurred regardless of whether the past contextual movement was performed actively, passively, or shown visually. In force field studies, it has been shown that motor memories generalize locally and that the level of compensation decays as a function of movement angle away from the trained movement. Here we examine if the contextual effect of past movement exhibits similar patterns of generalization and whether it can explain behavior seen in interference studies. Using a single force-field learning task, the directional tuning curves of both the prior contextual movement and the subsequent force field adaptive movements were measured. The adaptation movement direction showed strong directional tuning, decaying to zero by 90° relative to the training direction. The contextual movement direction exhibited a similar directional tuning, although the effect was always above 60%. We then investigated the directional tuning of the passive contextual movement using interference tasks, where the contextual movements that uniquely specified the force field direction were separated by ±15° or ±45°. Both groups showed a pronounced tuning effect, which could be well explained by the directional tuning functions for single force fields. Our results show that contextual effect of past movement influences predictive force compensation, even when adaptation does not require contextual information. However, when such past movement contextual information is crucial to the task, such as in an interference study, it plays a strong role in motor memory learning and recall. This work demonstrates that similar tuning responses underlie both generalization of movement direction during dynamic learning and contextual movements in both single force field and interference tasks

A New Approach for Quality Management in Pervasive Computing Environments

This paper provides an extension of MDA called Context-aware Quality Model Driven Architecture (CQ-MDA) which can be used for quality control in pervasive computing environments. The proposed CQ-MDA approach based on ContextualArchRQMM (Contextual ARCHitecture Quality Requirement MetaModel), being an extension to the MDA, allows for considering quality and resources-awareness while conducting the design process. The contributions of this paper are a meta-model for architecture quality control of context-aware applications and a model driven approach to separate architecture concerns from context and quality concerns and to configure reconfigurable software architectures of distributed systems. To demonstrate the utility of our approach, we use a videoconference system.Comment: 10 pages, 10 Figures, Oral Presentation in ECSA 201

Adaptive Process Management in Cyber-Physical Domains

The increasing application of process-oriented approaches in new challenging cyber-physical domains beyond business computing (e.g., personalized healthcare, emergency management, factories of the future, home automation, etc.) has led to reconsider the level of flexibility and support required to manage complex processes in such domains. A cyber-physical domain is characterized by the presence of a cyber-physical system coordinating heterogeneous ICT components (PCs, smartphones, sensors, actuators) and involving real world entities (humans, machines, agents, robots, etc.) that perform complex tasks in the “physical” real world to achieve a common goal. The physical world, however, is not entirely predictable, and processes enacted in cyber-physical domains must be robust to unexpected conditions and adaptable to unanticipated exceptions. This demands a more flexible approach in process design and enactment, recognizing that in real-world environments it is not adequate to assume that all possible recovery activities can be predefined for dealing with the exceptions that can ensue. In this chapter, we tackle the above issue and we propose a general approach, a concrete framework and a process management system implementation, called SmartPM, for automatically adapting processes enacted in cyber-physical domains in case of unanticipated exceptions and exogenous events. The adaptation mechanism provided by SmartPM is based on declarative task specifications, execution monitoring for detecting failures and context changes at run-time, and automated planning techniques to self-repair the running process, without requiring to predefine any specific adaptation policy or exception handler at design-time

Context Aware Adaptable Applications - A global approach

Actual applications (mostly component based) requirements cannot be expressed without a ubiquitous and mobile part for end-users as well as for M2M applications (Machine to Machine). Such an evolution implies context management in order to evaluate the consequences of the mobility and corresponding mechanisms to adapt or to be adapted to the new environment. Applications are then qualified as context aware applications. This first part of this paper presents an overview of context and its management by application adaptation. This part starts by a definition and proposes a model for the context. It also presents various techniques to adapt applications to the context: from self-adaptation to supervised approached. The second part is an overview of architectures for adaptable applications. It focuses on platforms based solutions and shows information flows between application, platform and context. Finally it makes a synthesis proposition with a platform for adaptable context-aware applications called Kalimucho. Then we present implementations tools for software components and a dataflow models in order to implement the Kalimucho platform

SmartPM: Automated Adaptation of Dynamic Processes

In this demonstration paper, we present the first working version of SmartPM, a Process Management System that is able to automatically adapt dynamic processes at run-time when unanticipated exceptions occur, thus requiring no specification of recovery policies at design-time