With the development of the Internet of Things (IoT) and the Internet, new kinds of services based on IoT devices will benefit everyone. As a key step in achieving a complex business structure based ...on a massive number of IoT devices, establishing an effective service composition is extremely important. The emerging architecture of composition is related to process management and is subject to security risks, such as privacy leaks. Traditional service composition methods have difficulty verifying the timed privacy requirements of an IoT service composition. Therefore, this paper proposes an automatic method of transforming Business Process Execution Language (BPEL) into timed automata for formal verification, with the aim of formalizing timed privacy requirements for the IoT service composition and verifying the formal model returned to the UPPAAL supporting tool. First, a privacy requirement template is introduced to analyze the structure of the IoT service composition. Then, a timed computation tree logic (TCTL) property formula template is used to describe the privacy requirements, especially time constraints. Second, an extended timed I/O automata model, namely, the Sensitive Data Timed I/O Automata (SDTIOA) model, is proposed to formalize communication behavior, sensitive data treatment, and service time. Third, the corresponding transformation rules and algorithms are designed for BPEL and SDTIOA. These models can be adjusted through user interaction. Next, as a practical engineering application, we develop a prototype to show how to work with UPPAAL and generate UPPAAL code from SDTIOA code. Finally, a case study is discussed to illustrate the processes of modeling and timed verification for an IoT service composition.
Este artículo presenta el análisis de un caso de asignación de visas americanas mediante la extracción de información de diferentes entidades. Para este problema se utilizan las siguientes fuentes de ...datos: i) información personal del solicitante, ii) información de los bienes inmuebles de la persona, y iii) el historial crediticio proveniente de entidades bancarias. Para la extracción de la información se crearon interfaces que simularon el funcionamiento de dichas entidades, así como sus respectivas bases de datos y servicios web. Para el envío de datos, se implementó en la aplicación, el uso de una arquitectura orientada a servicios (SOA) mediante el desarrollo de un sistema de orquestación de servicios. En este contexto, se aplicaron conceptos del lenguaje BPEL, cuya finalidad es demostrar la importancia de una orquestación de servicios en empresas u organizaciones y la gran utilidad de disponer de servicios integrados. Los conceptos aplicados en el desarrollo del sistema final, corroboran su utilización, puesto que los módulos desarrollados, pueden integrarse a otros sin que exista la necesidad de volver a diseñarlos desde cero, lo que representa una ayuda sustancial en la búsqueda de soluciones óptimas para infraestructuras TI.
Web services are becoming increasingly popular technologies for modern organizations to improve their cooperation and collaboration through building new software systems by composing pre-built ...services. Such services are typically composed and executed through BPEL (Business Process Execution Language) processes. Like any other software artifact, such processes are frequently changed to add new or modify existing functionalities or adapt to environmental changes. However, poorly planned changes may introduce BPEL process design defects known as anti-patterns or defects. The presence of defects often leads to a regression in software quality. In this paper, we introduce an automated approach to predict the presence of defects in BPEL code using Multi-Objective Genetic Programming (MOGP). Our approach consists of learning from real-world instances of each service-based business process defect (i.e., anti-pattern) type to infer prediction rules based on the combinations of process metrics and their associated threshold values. We evaluate our approach based on a dataset of 178 real-world business processes that belong to various application domains, and a variety of BPEL process defect types such as data flow and portability defects. The statistical analysis of the achieved results shows the effectiveness of our approach in identifying defects compared with state-of-the-art techniques with a median accuracy of 91%.
•Predicting business process defects is a complex and time-consuming task.•Business process defects as a multi-objective optimization problem.•Prediction rules generated by using a multi-objective evolutionary algorithm.•An empirical evaluation on five types of business process defects.•Multi-objective evolutionary algorithms achieve better performance than machine learning to predict business process defects.
•The Web of Things is a new paradigm in which everyday objects are connected to the Internet using popular Web technologies. Connecting smart things in a network is not enough to create added value; ...it should be possible to compose these objects together to create processes capable of responding to the most complex requests.•These processes respect precise time constraints to ensure that the functions invoked are executed in the right order. Exceeding or anticipating these time intervals can cause the entire process to become out of sync.•Although BPEL is a powerful orchestration language, it is not designed to support REST Web services. BPEL is extended to accommodate REST constraints. Also, BPEL specification is enriched by time attributes to improve its temporal expressiveness.•Such manual addition requires verification of process time consistency to ensure its validity before execution. Formal verification intervenes to detect any conflicts once the user creates the scenario.•The smart home is a promising concept, offering a range of advantages for its occupants. Internet-connected objects are managed according to a pre-defined time scenario.
The Web of Things (WoT) is a new paradigm in which everyday objects are connected to the Internet using popular Web technologies. The smart things are abstracted into RESTful Web services to facilitate their manipulation. The composition of these objects within the same business process creates an automated, time-synchronized routine that can perform even the most complex tasks. BPEL is an orchestration language that defines the process responsible for coordinating the Web services involved. However, this language presents some limitations in this context. BPEL 2.0 does not support RESTful Web services; its specification is incompatible with this architectural style of services. Moreover, its temporal expressivity is insufficient to cover all the constraints that may arise when composing services. This work aims to adapt BPEL to the requirements of the WoT environment, enabling it to create processes that invoke the smart things in precise time intervals. The solution is to exploit one of BPEL's strengths: its extensibility. The BPEL specification is enriched with four activities that reflect the REST uniform interface. They include the necessary attributes to send the request to the target object and receive the response in convened format representation. Also, temporal attributes are added to BPEL elements to schedule their start, end, and duration of execution. The manual addition of these temporal values requires a verification of their accuracy. The BPEL process must be reviewed to ensure its validity before its execution. A temporal Petri Net is proposed to detect any conflicts or inconsistencies between BPEL activities. As a result, associating the formal model with the extension allows BPEL to orchestrate smart things represented by RESTful Web services according to a well-defined temporal scenario. They respect the REST constraints and provide the BPEL activities with temporal attributes for efficient time management. The approach can be applied in all application areas to create temporal scenarios.
Summary
Petri nets are frequently used formal tools to analyze the compatibility of interactive service processes described by Web Services Business Process Execution Language (WS‐BPEL). However, the ...traditional methods based on Petri nets were with a high computable complexity for state space explosion. To resolve such problem, a logic Petri net–based path detecting method for compatibility analysis of interactive service processes is proposed. From the provided mapping rules, the service process described by WS‐BPEL is modeled as a service net based on logic Petri nets. The evaluation of interactive compatibility of two service processes is converted to analyze whether their service nets can be composed as a non‐blocked synthetic service net. The non‐blocked property is checked by detecting the reachability of the potential connected paths in a service net. To reduce the complexity of computing the connected paths in a service net, we propose a merge‐reduced method to generate the path expression of its skeleton service net. The potential connected paths of a service net can be obtained by unfolding the path expression. Compared with the traditional method based Petri nets, the proposed method is with high efficiency and it can greatly alleviate the problem of state space explosion in analyzing interactive compatibility of service processes.
Service composition, which is the integration of heterogeneous Web-accessible services, has introduced an open phenomenon for creating software systems that are deployed in an unpredictable execution ...context, where changes in the requirements, user preferences, and component services frequently occur. The consideration of adaptability in designing such systems is necessary in this unstable and volatile environment. There have been intensive efforts on solutions to make service compositions adaptable, but little attention is given to the evaluation of such adaptability. This paper proposes a set of metrics to quantify the adaptability of service compositions that are specified from the adaptive WS-BPEL-based frameworks. The metrics are based on two adaptability dimensions: the structure and binding variabilities. Structure variability, enables runtime changes to the composition workflow while binding variability, allows dynamic binding to concrete partner services. We evaluate the metrics through a case study, utilising variants of a travel booking process specified from different adaptive WS-BPEL-based frameworks found in the literature. The metrics are applicable to a wide spectrum of adaptive service compositions and their frameworks. A support tool is also developed to automate metrics computation. Through the metrics, adaptability of service compositions and their frameworks can be assessed and compared. This would facilitate design decisions in building flexible and robust services where adaptability is a first class concern.
•Adaptability measurement is concerned with the variability in both process workflow and binding to partner services.•Adaptability is compared regardless of process size and specification framework.•Process specification frameworks are compared based on the maximum process adaptability they can offer.•The measurement raises designers’ awareness on adaptability, to facilitate design decisions towards composing quality systems.
The proliferation of smartphones and sensor-based networks has led to a greater need for context-aware applications and pervasive business processes. One of the key approaches that seek to satisfy ...this need is context-aware service composition. Service composition can be achieved in two ways, i.e., service choreography and service orchestration. Embedding the context into an orchestrated composite service enhances its flexibility, but makes its development and execution more complicated. This study aims to reduce this complexity by introducing the CA-BPEL approach. Our proposed approach enables developers to turn a standard orchestrated service into a context-aware orchestrated service, consistent with the standard WS-BPEL language. This study applies the Design Science Research Methodology, in which we evaluate CA-BPEL by using a tourism demonstration along with the conduction of a usability survey that shows the convenience of the proposed approach. We also compare our proposed approach with 14 related studies. Our investigations suggest that CA-BPEL has much potential to facilitate the development and execution of context-aware service compositions.
Current Web service technology is evolving towards a simpler approach to define Web service APIs that challenges the assumptions made by existing languages for Web service composition. RESTful Web ...services introduce a new kind of abstraction, the resource, which does not fit well with the message-oriented paradigm of the Web service description language (WSDL). RESTful Web services are thus hard to compose using the Business Process Execution Language (WS-BPEL), due to its tight coupling to WSDL. The goal of the BPEL for REST extensions presented in this paper is twofold. First, we aim to enable the composition of both RESTful Web services and traditional Web services from within the same process-oriented service composition language. Second, we show how to publish a BPEL process as a RESTful Web service, by exposing selected parts of its execution state using the REST interaction primitives. We include a detailed example on how BPEL for REST can be applied to orchestrate a RESTful e-Commerce scenario and discuss how the proposed extensions affect the architecture of a process execution engine.
PDF
