Alan De Renzis

Semantic-structural assessment scheme for integrability in service-oriented applications

This work improves a novel Service Selection Method for the development of Service-Oriented Applications in the context of the Service-Oriented Computing (SOC) paradigm. We have defined a Semantic-Structural Scheme to assess Web Services on Interface Compatibility exploring the available information from WSDL documents. The structural information involves data types from return, parameters and exceptions. The semantic information concerns identifiers from parameters and operation names. The lexical database WordNet is used as a semantic basis. Two appraisal values were defined: compatibility gap and adaptability gap. The former is centered on functional aspects. The latter explains the adaptation effort to a successful integration. We validated those appraisals values through different experiments with a data-set of 465 real-life Web Services and measured the results using three metrics from the Information Retrieval field.

Microservices Identification Through Interface Analysis

The microservices architectural style is gaining more and more momentum for the development of applications as suites of small, autonomous, and conversational services, which are then easy to understand, deploy and scale. One of today’s problems is finding the adequate granularity and cohesiveness of microservices, both when starting a new project and when thinking of transforming, evolving and scaling existing applications. To cope with these problems, the paper proposes a solution based on the semantic similarity of foreseen/available functionality described through OpenAPI specifications. By leveraging a reference vocabulary, our approach identifies potential candidate microservices, as fine-grained groups of cohesive operations (and associated resources). We compared our approach against a state-of-the-art tool, sampled microservices-based applications and decomposed a large dataset of Web APIs. Results show that our approach is able to find suitable decompositions in some 80% of the cases, while providing early insights about the right granularity and cohesiveness of obtained microservices.

A domain independent readability metric for web service descriptions

Web Services are influencing most IT-based industries as the basic building block of business infrastructures. A Web Service has an interface described in a machine-processable format (specifically WSDL). Service providers expose their services by publishing the corresponding WSDL documents. Service consumers can learn about service capability and how to interact with the services. Service descriptions (WSDL documents) should be ideally understood easily by service stakeholders so that the process of consuming services is simplified. In this work we present a practical metric to quantify readability in WSDL documents - attending to their semantics by using WordNet as the underlying concept hierarchy. In addition, we propose a set of best practices to be used during the development of WSDL documents to improve their readability. To validate our proposals, we performed both qualitative and quantitative experiments. A controlled survey with a group of (human) service consumers showed that software engineers required less time and effort to analyze WSDL documents with higher readability values. Other experiment compares readability values of a dataset of real-life WSDL documents from the industry before and after modifying them to adhere to the readability best practices proposed in this paper. We detected a significant readability improvement for WSDL documents written according to the best practices. In another experiment, we applied existing readability metrics for natural language texts detecting their unsuitability to the Web Service context. Lastly, we analyzed the readability best practices identifying their useful applicability to the industry. HighlightsA practical metric to quantify readability in Web Services descriptions (WSDL).A set of best practices to be used during the development of WSDL documents to improve their readability.A controlled survey has been done to show the effort reduction of software engineers to analyze WSDL documents with high readability values.Building documents following the best practices improve their readability values as we experienced with a dataset of real WSDL documents.

Case-based Reasoning for Web Service Discovery and Selection

Web Service discovery and selection deal with the retrieval of the most suitable Web Service, given a required functionality. Addressing an effective solution remains difficult when only functional descriptions of services are available. In this paper, we propose a solution by applying Case-based Reasoning, in which the resemblance between a pair of cases is quantified through a similarity function. We show the feasibility of applying Case-based Reasoning for Web Service discovery and selection, by introducing a novel case representation, learning heuristics and three different similarity functions. We also experimentally validate our proposal with a dataset of 62 real-life Web Services, achieving competitive values in terms of well-known Information Retrieval metrics.

A structural-semantic web service selection approach to improve retrievability of web services

Service-Oriented Computing promotes building applications by consuming and reusing Web Services. However, the selection of adequate Web Services given a client application is still a major challenge. The effort of assessing and adapting candidate services could be overwhelming due to the “impedance” of Web Service interfaces expected by clients versus the actual interfaces of retrieved Web Services. In this work, we present a novel structural-semantic approach to help developers in the retrieval and selection of services from a service registry. The approach is based on a comprehensive structural scheme for service Interface Compatibility analysis, and WordNet as the semantic support to assess identifiers of operations and parameters. We also empirically analyze, compare and contrast the performance of three service selection methods: a pure structural approach, a pure semantic approach, and the structural-semantic (hybrid) approach proposed in this work. The experimental analysis was performed with two data-sets of real-world Web Services and a service discovery support already published in the literature. Results show that our hybrid service selection approach improved effectiveness in terms of retrievability of Web Services compared to the other approaches.

Assessing Web Services Interfaces with Lightweight Semantic Basis

In the last years, Web Services have become the technological choice to materialize the Service-Oriented Computing paradigm. However, a broad use of Web Services requires efficient approaches to allow service consumption from within applications. Currently, developers are compelled to search for suitable services mainly by manually exploring Web catalogs, which usually show poorly relevant information, than to provide the adequate “glue-code” for their assembly. This implies a large effort into discovering, selecting and adapting services. To overcome these challenges, this paper presents a novel Web Service Selection Method. We have defined an Interface Compatibility procedure to assess structural-semantic aspects 1002 M. Garriga, A. De Renzis, A. Flores, A. Cechich, A. Zunino from functional specifications – in the form of WSDL documents – of candidate Web Services. Two different semantic basis have been used to define and implement the approach: WordNet, a widely known lexical dictionary of the English language; and DISCO, a database which indexes co-occurrences of terms in very large text collections. We performed a set of experiments to evaluate the approach regarding the underlying semantic basis and against third-party approaches with a data-set of real-life Web Services. Promising results have been obtained in terms of well-known metrics of the Information Retrieval field.

Testing-supported Case-Based Reasoning for Web Service Selection

Web Service discovery and selection deals with the retrieval of the most suitable Web Service, given a required functionality. Addressing an effective solution remains difficult when only functional descriptions of services are available. The Artificial Intelligence (AI) field have contributed significantly to support the Web Services lifecycle. In this paper, we propose an extension of a previous approach that applied Case-Based Reasoning (CBR) for Web Service Selection, in which Web Services are behaviorally tested for conformance of a given required functionality.

Assessing readability of Web service interfaces

A Web Service has an interface described in a machine-processable format (specifically WSDL). Service providers expose their services by publishing their WSDL documents. Service consumers can learn about service capability and how to interact with the services. Service descriptions (WSDL documents) should be ideally understood easily by service stakeholders so that the process of consuming services is simplified. In this work we present a practical metric to quantify readability in WSDL documents. We adapted and extended an existing semantic readability metric to focus on WSDL documents by using WordNet as the underlying concept hierarchy. Finally, we performed a qualitative experiment: a controlled survey with a group of service consumers. The results showed that consumers (software engineers) required less time and effort to analyze WSDL documents with higher readability values.

Web Services Interfaces Assessment through Semantic Similarity of Terms

This work presents an improvement on a novel Selection Method to develop applications in the context of the Service-Oriented Computing paradigm. We have defined an Interface Compatibility procedure to assess Web Services by exploring the available information from WSDL documents. Such information involves data types from return, parameters and exceptions, and identifiers from parameters and operation names. The lexical database WordNet was originally used as a semantic basis to assess terms from identifiers. In this paper we use the DISCO database as an alternative, to evaluate the independence of the approach w.r.t. the semantic basis. We made a comparative analysis through different experiments with a data-set of 465 real-life Web Services and measured the results using metrics from the Information Retrieval field.