George Baryannis

Lifecycle management of service-based applications on multi-clouds: a research roadmap

In this paper we identify current challenges in the deployment of complex distributed applications on multiple Cloud providers and review the state of the art in model-driven Cloud software engineering. Challenges include lack of support for heterogeneous Cloud providers; limited matchmaking between application requirements and Cloud capabilities; lack of meaningful cross-platform Cloud resource descriptions; lack of lifecycle management of Cloud applications; inadequate cross-layer monitoring and adaptation based on event correlation; and others. In this paper we propose solutions to these challenges and highlight the expected benefits in the context of a complex distributed application.

WSSL: a fluent calculus-based language for web service specifications

In order to effectively discover and invoke a Web service, the provider must supply a complete specification of its behavior, with regard to its inputs, outputs, preconditions and effects. Devising such complete specifications comes with many issues that have not been adequately addressed by current service description efforts, such as WSDL, SAWSDL, OWL-S and WSMO. These issues involve the frame, ramification and qualification problems, which deal with the succinct and flexible representation of non-effects, indirect effects and preconditions, respectively. We propose WSSL, a novel specification language for services, based on the fluent calculus, that is expressly designed to address the aforementioned issues. Also, a tool is implemented that translates WSSL specifications to FLUX programs and allows for service validation based on user-defined goals.

Rule-Based Real-Time ADL Recognition in a Smart Home Environment

This paper presents a rule-based approach for both offline and real-time recognition of Activities of Daily Living (ADL), leveraging events produced by a non-intrusive multi-modal sensor infrastructure deployed in a residential environment. Novel aspects of the approach include: the ability to recognise arbitrary scenarios of complex activities using bottom-up multi-level reasoning, starting from sensor events at the lowest level; an effective heuristics-based method for distinguishing between actual and ghost images in video data; and a highly accurate indoor localisation approach that fuses different sources of location information. The proposed approach is implemented as a rule-based system using Jess and is evaluated using data collected in a smart home environment. Experimental results show high levels of accuracy and performance, proving the effectiveness of the approach in real world setups.

Fluent Calculus-Based Semantic Web Service Composition and Verification Using WSSL

We propose a composition and verification framework for Semantic Web Services specified using WSSL, a novel service specification language based on the fluent calculus, that addresses issues related to the frame, ramification and qualification problems. These deal with the succinct and flexible representation of non-effects, indirect effects and preconditions, respectively. The framework exploits the unique features of WSSL, allowing, among others, for: compositions that take into account ramifications of services; determining the feasibility of a composition a priori; and considering exogenous qualifications during the verification process. The framework is implemented using FLUX-based planning, supporting compositions with fundamental control constructs, including nondeterministic ones such as conditionals and loops. Performance is evaluated with regard to termination and execution time for increasingly complex synthetic compositions.

Deriving Specifications for Composite Web Services

We address the problem of synthesizing specifications for composite Web services, starting from those of their component services. Unlike related work in programming languages, we assume the definition of the component services (i.e. their code) to be unavailable - at best, they are known by a specification which (safely) approximates their functional behavior. Within this scenario, we deduce general formula schemes to derive specifications for basic constructs such as sequential, parallel compositions and conditionals and provide details on how to handle the special cases of loops and asynchronous execution. The resulting specifications facilitate service verification and service evolution as well as auditing processes, promoting trust between the involved partners.

The frame problem in Web service specifications

This work explores the frame problem and its effects in devising Web service specifications. The frame problem encompasses the issues raised when trying to concisely state in a specification that nothing changes except when explicitly mentioned otherwise. A motivating example of a composite service specification is presented and a solution approach is proposed, based on knowledge gained from related research on the frame problem in procedure specifications. Finally, an algorithm that applies the presented solution in order to transform existing OWL-S service descriptions to ones that are free from the frame problem is presented.

A specification-based QoS-aware design framework for service-based applications

Effective and accurate service discovery and composition rely on complete specifications of service behaviour, containing inputs and preconditions that are required before service execution, outputs, effects and ramifications of a successful execution and explanations for unsuccessful executions. The previously defined Web Service Specification Language (WSSL) relies on the fluent calculus formalism to produce such rich specifications for atomic and composite services. In this work, we propose further extensions that focus on the specification of QoS profiles, as well as partially observable service states. Additionally, a design framework for service-based applications is implemented based on WSSL, advancing state of the art by being the first service framework to simultaneously provide several desirable capabilities, such as supporting ramifications and partial observability, as well as non-determinism in composition schemas using heuristic encodings; providing explanations for unexpected behaviour; and QoS-awareness through goal-based techniques. These capabilities are illustrated through a comparative evaluation against prominent state-of-the-art approaches based on a typical SBA design scenario.

Supply Chain Risk Management and Artificial Intelligence: State of the Art and Future Research Directions

Supply chain risk management (SCRM) encompasses a wide variety of strategies aiming to identify, assess, mitigate and monitor unexpected events or conditions which might have an impact, mostly adverse, on any part of a supply chain. SCRM strategies often depend on rapid and adaptive decision-making based on potentially large, multidimensional data sources. These characteristics make SCRM a suitable application area for artificial intelligence (AI) techniques. The aim of this paper is to provide a comprehensive review of supply chain literature that addresses problems relevant to SCRM using approaches that fall within the AI spectrum. To that end, an investigation is conducted on the various definitions and classifications of supply chain risk and related notions such as uncertainty. Then, a mapping study is performed to categorise existing literature according to the AI methodology used, ranging from mathematical programming to Machine Learning and Big Data Analytics, and the specific SCRM task they address (identification, assessment or response). Finally, a comprehensive analysis of each category is provided to identify missing aspects and unexplored areas and propose directions for future research at the confluence of SCRM and AI.