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Qos-driven runtime adaptation of service oriented architectures
, 2009
"... Runtime adaptation is recognized as a viable way for a serviceoriented system to meet QoS requirements in its volatile operating environment. In this paper we propose a methodology to drive the adaptation of such a system, that integrates within a unified framework different adaptation mechanisms, t ..."
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Cited by 41 (8 self)
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Runtime adaptation is recognized as a viable way for a serviceoriented system to meet QoS requirements in its volatile operating environment. In this paper we propose a methodology to drive the adaptation of such a system, that integrates within a unified framework different adaptation mechanisms, to achieve a greater flexibility in facing different operating environments and the possibly conflicting QoS requirements of several concurrent users. To determine the most suitable adaptation action(s), the methodology is based on the formulation and solution of a linear programming problem, which is derived from a behavioral model of the system updated at runtime by a monitoring activity. Numerical experiments show the effectiveness of our approach. Besides the methodology, we also present a prototype tool that implements it.
MOSES: a Framework for QoS Driven Runtime Adaptation of Service-oriented Systems
"... Architecting software systems according to the service-oriented paradigm, and designing runtime self-adaptable systems are two relevant research areas in today’s software engineering. In this paper we address issues that lie at the intersection of these two important fields. First, we present a cha ..."
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Cited by 24 (3 self)
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Architecting software systems according to the service-oriented paradigm, and designing runtime self-adaptable systems are two relevant research areas in today’s software engineering. In this paper we address issues that lie at the intersection of these two important fields. First, we present a characterization of the problem space of self-adaptation for service-oriented systems, thus providing a frame of reference where our and other approaches can be classified. Then, we present MOSES, a methodology and a software tool implementing it to support QoS-driven adaptation of a service-oriented system. It works in a specific region of the identified problem space, corresponding to the scenario where a service-oriented system architected as a composite service needs to sustain a traffic of requests generated by several users. MOSES integrates within a unified framework different adaptation mechanisms. In this way it achieves a greater flexibility in facing various operating environments and the possibly conflicting QoS requirements of several concurrent users. Experimental results obtained with a prototype implementation of MOSES show the effectiveness of the proposed approach.
Autonomic Provisioning with Self-Adaptive Neural Fuzzy Control for Percentile-Based Delay Guarantee
"... Autonomic server provisioning for performance assurance is a critical issue in Internet services. It is challenging to guarantee that requests flowing through a multi-tier system will experience an acceptable distribution of delays. The difficulty is mainly due to highly dynamic workloads, the compl ..."
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Cited by 17 (10 self)
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Autonomic server provisioning for performance assurance is a critical issue in Internet services. It is challenging to guarantee that requests flowing through a multi-tier system will experience an acceptable distribution of delays. The difficulty is mainly due to highly dynamic workloads, the complexity of underlying computer systems, and the lack of accurate performance models. We propose a novel autonomic server provisioning approach based on a model-independent self-adaptive Neural Fuzzy Control (NFC). Existing model-independent fuzzy controllers are designed manually on a trial-and-error basis, and are often ineffective in the face of highly dynamic workloads. NFC is a hybrid of control-theoretical and machine learning techniques. It is capable of self-constructing its structure and adapting its parameters through fast online learning. We further enhance NFC to compensate for the effect of server switching delays. Extensive simulations demonstrate that, compared to a rule-based fuzzy controller and a Proportional-Integral controller, the NFC-based approach delivers superior performance assurance in the face of highly dynamic workloads. It is robust to variation in workload intensity, characteristics, delay target, and server switching delays. We demonstrate the feasibility and performance of the NFC-based approach with a testbed implementation in virtualized blade servers hosting a multi-tier online auction benchmark.
A rigorous architectural approach to adaptive software engineering
- Journal of Computer Science and Technology
, 2009
"... Abstract The engineering of distributed adaptive software is a complex task which requires a rigorous approach. Software architectural (structural) concepts and principles are highly beneficial in specifying, designing, analysing, constructing and evolving distributed software. A rigorous architectu ..."
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Cited by 14 (0 self)
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Abstract The engineering of distributed adaptive software is a complex task which requires a rigorous approach. Software architectural (structural) concepts and principles are highly beneficial in specifying, designing, analysing, constructing and evolving distributed software. A rigorous architectural approach dictates formalisms and techniques that are compositional, components that are context independent and systems that can be constructed and evolved incrementally. This paper overviews some of the underlying reasons for adopting an architectural approach, including a brief “rational history ” of our research work, and indicates how an architectural model can potentially facilitate the provision of self-managed adaptive software system.
FORMS: a FOrmal Reference Model for Self-adaptation
"... Self-adaptive software systems are an emerging class of systems that adjust their behavior at runtime to achieve certain functional or quality of service objectives. The construction of such systems has shown to be significantly more challenging than traditional systems, partly because researchers a ..."
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Cited by 12 (4 self)
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Self-adaptive software systems are an emerging class of systems that adjust their behavior at runtime to achieve certain functional or quality of service objectives. The construction of such systems has shown to be significantly more challenging than traditional systems, partly because researchers and practitioners have been struggling with the lack of a precise method of describing, comparing, and evaluating alternative architectural choices. In this paper, we introduce a reference model, entitled FOrmal Reference Model for Self-adaptation (FORMS), which intends to alleviate this pressing issue. FORMS consists of a small number of formally specified modeling primitives that correspond to the key variation points within self-adaptive software systems, and a set of relationships that guide their composition. We present our experiences with applying FORMS to several existing systems, which not only demonstrates its ability to precisely illuminate their underlying characteristics, but also its potential as a method of rigorously specifying architectural patterns for this domain.
URL: A Unified Reinforcement Learning Approach for Autonomic Cloud Management
"... Cloud computing is emerging as an increasingly important service-oriented computing paradigm. Management is a key to providing accurate service availability and performance data, as well as enabling real-time provisioning that automatically provides the capacity needed to meet service demands. In th ..."
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Cited by 11 (3 self)
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Cloud computing is emerging as an increasingly important service-oriented computing paradigm. Management is a key to providing accurate service availability and performance data, as well as enabling real-time provisioning that automatically provides the capacity needed to meet service demands. In this paper, we present a unified reinforcement learning approach, namely URL, to automate the configuration processes of virtualized machines and appliances running in the virtual machines. The approach lends itself to the application of real-time autoconfiguration of clouds. It also makes it possible to adapt the VM resource budget and appliance parameter settings to the cloud dynamics and the changing workload to provide service quality assurance. In particular, the approach has the flexibility to make a good trade-off between system-wide utilization objectives and appliance-specific SLA optimization goals. Experimental results on Xen VMs with various workloads demonstrate the effectiveness of the approach. It can drive the system into an optimal or near-optimal configuration setting in a few trial-and-error iterations. 1.
Toward Risk Assessment as a Service in Cloud Environments
"... Security and privacy assessments are considered a best practice for evaluating a system or application for potential risks and exposures. Cloud computing introduces several characteristics that challenge the effectiveness of current assessment approaches. In particular, the on-demand, automated, mul ..."
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Cited by 10 (0 self)
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Security and privacy assessments are considered a best practice for evaluating a system or application for potential risks and exposures. Cloud computing introduces several characteristics that challenge the effectiveness of current assessment approaches. In particular, the on-demand, automated, multi-tenant nature of cloud computing is at odds with the static, human process-oriented nature of the systems for which typical assessments were designed. This paper describes these challenges and recommends addressing them by introducing risk assessment as a service. 1.
A taxonomy and survey of self-protecting software systems
- 2012 ICSE Workshop on Software Engineering for Adaptive and Self-Managing Systems (SEAMS
"... Self-protecting software systems are a class of autonomic systems capable of detecting and mitigating security threats at runtime. They are growing in importance, as the stovepipe static methods of securing software systems have shown inadequate for the challenges posed by modern software systems. S ..."
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Cited by 9 (1 self)
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Self-protecting software systems are a class of autonomic systems capable of detecting and mitigating security threats at runtime. They are growing in importance, as the stovepipe static methods of securing software systems have shown inadequate for the challenges posed by modern software systems. Self-protection, like other self- * properties, allows the system to adapt to the changing environment through autonomic means without much human intervention, and can thereby be responsive, agile, and cost effective. While existing research has made significant progress towards autonomic and adaptive security, gaps and challenges remain. This paper presents a significant extension of our preliminary study in this area. In particular, unlike our preliminary study, here we have followed a systematic literature review process, which has broadened the scope of our study and strengthened the validity of our conclusions. By proposing and applying a comprehensive taxonomy to classify and characterize the state-of-the-art research in this area, we have identified key patterns, trends and challenges in the existing approaches, which reveals a number of opportunities that will shape the focus of future research efforts.
Automated Design of Self-Adaptive Software with Control-Theoretical Formal Guarantees
- Proc. 36th International Conference on Software Engineering
, 2014
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Claims and Supporting Evidence for Self-Adaptive Systems – A Literature Study”. In: SEAMS
, 2012
"... Abstract—Despite the vast body of work on self-adaption, no systematic study has been performed on the claims associated with self-adaptation and the evidence that exists for these claims. As such an insight is crucial for researchers and engineers, we performed a literature study of the research re ..."
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Cited by 8 (2 self)
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Abstract—Despite the vast body of work on self-adaption, no systematic study has been performed on the claims associated with self-adaptation and the evidence that exists for these claims. As such an insight is crucial for researchers and engineers, we performed a literature study of the research results from SEAMS since 2006 and the associated Dagstuhl seminar in 2008. The study shows that the primary claims of self-adaptation are improved flexibility, reliability, and performance of the system. On the other hand, the tradeoffs implied by self-adaptation have not received much attention. Evidence is obtained from basic examples, or simply lacking. Few systematic empirical studies have been performed, and no industrial evidence is reported. From the study, we offer the following recommendations to move the field forward: to improve evaluation, researchers should make their assessment methods, tools and data publicly available; to deal with poor discussion of limitations, conferences/workshops should require an explicit section on limitations in engineering papers; to improve poor treatment of tradeoffs, this aspect should be an explicit subject of reviews; and finally, to enhance industrial validation, the best academy-industry efforts could be formally recognized by the community.1 I.
