A Tool Chain for Constructing QoS-aware Web Services

2012 ◽  
pp. 189-211
Author(s):  
Bernhard Hollunder ◽  
Ahmed Al-Moayed ◽  
Alexander Wahl
Keyword(s):  
Web Services ◽  
Dominant Role ◽  
Distributed Applications ◽  
Service Oriented Architectures ◽  
Tool Chain ◽  
Service Computing ◽  
Service Oriented ◽  
Development Support ◽  
Standard Components

Web services play a dominant role in service computing and for realizing service-oriented architectures (SOA), which define the architectural foundation for various kinds of distributed applications. In many business domains, Web services must exhibit quality attributes such as robustness, security, dependability, performance, scalability and accounting. As a consequence, there is a high demand to develop, deploy and consume Web services equipped with well-defined quality of service (QoS) attributes – so-called QoS-aware Web services. Currently, there is only limited development support for the creation of QoS-aware Web services, though. In this work we present a tool chain that facilitates development, deployment and testing of QoS-aware Web services. The tool chain has following features: i) integration of standard components such as widely used IDEs, ii) usage of standards and specifications, and iii) support for various application servers and Web services infrastructures.

On Modelling Non-Functional Properties of Semantic Web Services

2012 ◽  
pp. 61-85
Author(s):  
Ioan Toma ◽  
Flavio De Paoli ◽  
Dieter Fensel
Keyword(s):  
Web Services ◽  
Semantic Web ◽  
Functional Properties ◽  
Building Blocks ◽  
Distributed Applications ◽  
Semantic Web Services ◽  
Service Oriented Architectures ◽  
Language Support ◽  
Research Problems ◽  
Service Oriented

Service-Oriented Architectures (SOAs) are a widespread solution for realizing distributed applications. Empowered by semantic technologies these architectures will evolve in what is known as Semantically Enabled Service Oriented Architectures (SESAs) providing automatic support for various service related tasks such as discovery, ranking, composition, etc. Services are the core building blocks of both SOA- and SESA- based systems and therefore modelling various aspects of services becomes a fundamental challenge to any enterprise building SOA solutions. Among these aspects, non-functional properties of a service need to be addressed given the high dynamism of any SOA-based system. Non-functional properties descriptions are highly relevant for many of the service related tasks such as discovery, ranking, selection, and negotiation. This chapter investigates several research problems which arise in the area of Semantic Web services, namely how to describe non-functional properties of services, what models are required, and what is the proper language support for describing Non-functional Properties. Our solution was developed, and is part of the Web Service Modelling Ontology, one of the major initiatives in Semantic Web services area. We present a comprehensive set of ontological models for non-functional properties, our approach to attach non-functional properties descriptions to services, and the language support needed to formalize non-functional properties descriptions.

Adaptive BPEL Service Compositions via Variability Management

2019 ◽  
Vol 16 (1) ◽  
pp. 37-69
Author(s):  
Chang-ai Sun ◽  
Zhen Wang ◽  
Ke Wang ◽  
Tieheng Xue ◽  
Marco Aiello
Keyword(s):  
Web Services ◽  
Vertical Integration ◽  
Service Composition ◽  
Distributed Applications ◽  
Service Oriented Architectures ◽  
Business Process Execution Language ◽  
Service Oriented ◽  
Variability Management ◽  
Business Process Execution ◽  
Development Paradigm

Service-Oriented Architectures are a popular development paradigm to enable distributed applications constructed from independent web services. When coordinated, web services are an infrastructure to fulfill dynamic and vertical integration of business. They may face frequent changes of both requirements and execution environments. Static and predefined service compositions using business process execution language (BPEL) are not able to cater for such rapid and unpredictable context shifts. The authors propose a variability management-based adaptive and configurable service composition approach that treats changes as first-class citizens and consists of identifying, expressing, realizing, and managing changes of service compositions. The proposed approach is realized with a language called VxBPEL to support variability in service compositions and a platform for design, execution, analysis, and maintenance of VxBPEL-based service compositions. Four case studies validate the feasibility of the proposed approach while exhibiting good performance of the supporting platform.

A Two Phases Self-healing Framework for Service-oriented Systems

2021 ◽  
Vol 15 (2) ◽  
pp. 1-25
Author(s):  
Amal Alhosban ◽  
Zaki Malik ◽  
Khayyam Hashmi ◽  
Brahim Medjahed ◽  
Hassan Al-Ababneh
Keyword(s):  
Web Services ◽  
A Priori ◽  
Fault Management ◽  
Service Selection ◽  
Exception Handling ◽  
Self Healing ◽  
Service Oriented Architectures ◽  
Service Oriented ◽  
Improved Performance ◽  
High Level

Service-Oriented Architectures (SOA) enable the automatic creation of business applications from independently developed and deployed Web services. As Web services are inherently a priori unknown, how to deliver reliable Web services compositions is a significant and challenging problem. Services involved in an SOA often do not operate under a single processing environment and need to communicate using different protocols over a network. Under such conditions, designing a fault management system that is both efficient and extensible is a challenging task. In this article, we propose SFSS, a self-healing framework for SOA fault management. SFSS is predicting, identifying, and solving faults in SOAs. In SFSS, we identified a set of high-level exception handling strategies based on the QoS performances of different component services and the preferences articled by the service consumers. Multiple recovery plans are generated and evaluated according to the performance of the selected component services, and then we execute the best recovery plan. We assess the overall user dependence (i.e., the service is independent of other services) using the generated plan and the available invocation information of the component services. Due to the experiment results, the given technique enhances the service selection quality by choosing the services that have the highest score and betters the overall system performance. The experiment results indicate the applicability of SFSS and show improved performance in comparison to similar approaches.

TESTING AND FORMAL VERIFICATION OF SERVICE ORIENTED ARCHITECTURES

2009 ◽  
Vol 16 (02) ◽  
pp. 137-162 ◽  
Author(s):  
JOHN C. SLOAN ◽  
TAGHI M. KHOSHGOFTAAR
Keyword(s):  
Formal Verification ◽  
Software Agents ◽  
Third Party ◽  
Software Quality Assurance ◽  
Middle Ground ◽  
Network Resources ◽  
Service Oriented Architectures ◽  
Engineering Problems ◽  
Service Oriented

We examine two open engineering problems in the area of testing and formal verification of internet-enabled service oriented architectures (SOA). The first involves deciding when to formally and exhaustively verify versus when to informally and non-exhaustively test. The second concerns scalability limitations associated with formal verification, to which we propose a semi-formal technique that uses software agents. Finally, we assess how these findings can improve current software quality assurance practices. Addressing the first problem, we present and explain two classes of tradeoffs. External tradeoffs between assurance, performance, and flexibility are determined by the business needs of each application, whether it be in engineering, commerce, or entertainment. Internal tradeoffs between assurance, scale, and level of detail involve the technical challenges of feasibly verifying or testing an SOA. To help decide whether to exhaustively verify or non-exhaustively test, we present and explain these two classes of tradeoffs. Identifying a middle ground between testing and verification, we propose using software agents to simulate services in a composition. Technologically, this approach has the advantage of assuring the quality of compositions that are too large to exhaustively verify. Operationally, it supports testing these compositions in the laboratory without access to source code or use of network resources of third-party services. We identify and exploit the structural similarities between agents and services, examining how doing so can assure the quality of service compositions.

scholarly journals Αρχιτεκτονικές και μηχανισμοί διασφάλισης ποιότητας υπηρεσιών σε υπηρεσιοστρεφείς υποδομές

2009 ◽  
Author(s):  
Ανδρέας Μενύχτας
Keyword(s):  
Quality Of Service ◽  
Service Oriented Architectures ◽  
Service Oriented

Οι υπηρεσιοστρεφείς αρχιτεκτονικές (Service Oriented Architectures - SOA) αποτελούν αδιαμφισβήτητα την επικρατούσα τάση για την ανάπτυξη των σύγχρονων συστημάτων πληροφορικής και επικοινωνιών. Επιπρόσθετα, χαρακτηριστικό γνώρισμα όλων των σύγχρονων συστημάτων, και ειδικότερα αυτών με επιχειρηματικό προσανατολισμό, είναι η ανάγκη για διασφάλιση του επιπέδου παροχής ποιότητας υπηρεσιών (Quality of Service - QoS) για τους χρήστες τους, κάτι που καθορίζει τόσο την αποδοχή τους στο ευρύ κοινό όσο και την οικονομική βιωσιμότητά τους. Η διατριβή επικεντρώνεται στη μελέτη ολοκληρωμένων αρχιτεκτονικών και μηχανισμών με σκοπό τη διασφάλιση ποιότητας υπηρεσιών σε υπηρεσιοστρεφείς υποδομές (SOIs). Ο στόχος της διατριβής δεν είναι μόνο η διασφάλιση της ποιότητας υπηρεσιών η οποία μπορεί να ορίζεται γενικά ή μέσα από διεθνή πρότυπα αλλά και μεμονωμένα/ειδικά για κάθε υπηρεσία, όπως την αντιλαμβάνονται οι εμπλεκόμενες οντότητες κατά τη διαδικασία παροχής/χρήσης της και την εκφράζουν στη μεταξύ τους συμφωνία. Καθοριστικό στοιχείο για το επίπεδο της ποιότητας υπηρεσιών και τον τρόπο που αυτή παρέχεται είναι το επιχειρηματικό μοντέλο στο οποίο εντάσσεται η υποδομή και οι υπηρεσίες που προσφέρονται. Στο πλαίσιο αυτό αναλύεται, σχεδιάζεται και υλοποιείται μια σειρά από ολοκληρωμένες υπηρεσιοστρεφείς αρχιτεκτονικές λύσεις και μηχανισμούς που αντιμετωπίζουν τις προκλήσεις για την διασφάλιση της ποιότητας υπηρεσιών στον ευρύ τομέα των υπηρεσιοστρεφών υποδομών και των πλεγμάτων επόμενης γενιάς. Ιδιαίτερη έμφαση δίνεται σε εφαρμογές βιοϊατρικής, όπου προτείνονται και αξιολογούνται μηχανισμοί που διασφαλίζουν την ποιότητα υπηρεσιών μέσα από δυναμική δρομολόγηση και αποδοτικό υπολογισμό φόρτου εργασίας και χωρητικότητας. Παράλληλα μελετήθηκαν οι επιδόσεις των υποδομών και των μηχανισμών, τόσο από την πλευρά του χρήστη όσο και από την πλευρά του παρόχου υπηρεσιών, αναφορικά με επιχειρηματικές εφαρμογές όπως οι εφαρμογές πολυμέσων. Τέλος μελετήθηκε και παρουσιάζεται μια καινοτόμος αρχιτεκτονική προσέγγιση που αναπτύχθηκε με σκοπό να καλύψει τις ανάγκες διαδραστικών εφαρμογών πραγματικού χρόνου, οι οποίες εκτελούνται σε εικονικά περιβάλλοντα υπηρεσιοστρεφών υποδομών.

Generalized Demand-Driven Web Services

2014 ◽  
pp. 102-134 ◽  
Author(s):  
Mihai Horia Zaharia
Keyword(s):  
Web Services ◽  
Service Composition ◽  
Intelligent Agents ◽  
Human Life ◽  
Knowledge Society ◽  
Real Life ◽  
Service Oriented Architectures ◽  
Developed Economies ◽  
Novel Approach ◽  
Service Oriented

Highly developed economies are based on the knowledge society. A variety of software tools are used in almost every aspect of human life. Service-oriented architectures are limited to corporate-related business solutions. This chapter proposes a novel approach aimed to overcome the differences between real life services and software services. Using the design approaches for the current service-oriented architecture, a solution that can be implemented in open source systems has been proposed. As a result, a new approach to creating an agent for service composition is introduced. The agent itself is created by service composition too. The proposed approach might facilitate the research and development of Web services, service-oriented architectures, and intelligent agents.

Services and Service Computing

2013 ◽  
pp. 101-162
Keyword(s):  
Web Services ◽  
Heterogeneous Networks ◽  
Distributed Applications ◽  
Internet Technology ◽  
Computing Technology ◽  
Enterprise Integration ◽  
Web Based ◽  
Service Computing ◽  
The Core ◽  
The Web

Internet technology continues to grow fast and has now become the dominant computing technology in developing software and computing applications. By fully taking advantage of the quick development of the service concept and modeling, Web services technology, as part of Internet technology, has rapidly evolved and made a drastic impact on enterprise integration. A deployed Web based service, relying on a suite of Internet based standard protocols, is self-contained, self-describing, and network-neutral computing component. It can be readily deployed, published, located, and invoked over the heterogeneous networks. This chapter starts with a brief introduction to the concepts of services and enterprise service computing. The Web service’s technical fundamentals are then fully explored. XML, SOAP, WSDL, and UDDI as the core technologies are further explained in great detail. Implementation examples are finally used to demonstrate how the Web services technology can be typically applied in integrating distributed applications across an organization.

Automating the Generation of Joins in Large Databases and Web Services

2011 ◽  
pp. 123-140
Author(s):  
Sikha Bagui ◽  
Adam Loggins
Keyword(s):  
Web Services ◽  
Data Retrieval ◽  
Automate Data ◽  
Service Oriented Architectures ◽  
Data Usage ◽  
Large Databases ◽  
Service Oriented

In this data-centric world, as web services and service oriented architectures gain momentum and become a standard for data usage, there will be a need for tools to automate data retrieval. In this paper we propose a tool that automates the generation of joins in a transparent and integrated fashion in heterogeneous large databases as well as web services. This tool reads metadata information and automatically displays a join path and a SQL join query. This tool will be extremely useful for performing joins to help in the retrieval of information in large databases as well as web services.

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