Real-time Service-oriented Architecture Research Articles

Adaptive security architecture for protecting RESTful web services in enterprise computing environment

In this modern era of enterprise computing, the enterprise application integration (EAI) is a well-known industry-recognized architectural principle that is built based on loosely coupled application architecture, where service-oriented architecture (SOA) is the architectural pattern for the implementation of EAI, whose computational elements are called as “services.” Though SOA can be implemented in a wide range of technologies, the web services implementation of SOA becomes the current selective choice due to its simplicity that works on basic Internet protocols. Web service technology defines several supporting protocols and specifications such as SOAP and WSDL for communication with client and server for data interchange. A new architectural paradigm has emerged in SOA in recent years called REpresentational State Transfer (REST) that is also used to integrate loosely coupled service components, named RESTful web services, by system integration consortiums. This SOA implementation does not possess adequate security solutions within it, and its security is completely dependent on network/transport layer security that is obsolete owing to latest web technologies such as Web 2.0 and its upgraded version, Web 3.0. Vendor security products have major implementation constraints such as they need secured organizational environment and breach to SOA specifications, hence introducing new vulnerabilities. Herein, we examine the security vulnerabilities of RESTful web services in the view of popular OWASP rating methodologies and analyze the gaps in the existing security solutions. We hence propose an adaptive security solution for REST that uses public key infrastructure techniques to enhance the security architecture. The proposed security architecture is constructed as an adaptive way-forward Internet-of-Things (IoT) friendly security solution that is comprised of three cyclic parts: learn, predict and prevent. A novel security component named “intelligent security engine” is introduced which learns the possible occurrences of security threats on SOA using artificial neural networks learning algorithms, then it predicts the potential attacks on SOA based on obtained results by the developed theoretical security model, and the written algorithms as part of security solution prevent the SOA attacks. This paper is written to present one of such algorithms to prevent SOA attacks on RESTful web services along the discussion on the obtained results of the conducted proof-of-concept on the real-time SOA environment. A comparison of the proposed system with other competing solutions demonstrates its superiority.

Service-oriented approach to fault tolerance in CPSs

Cyber-physical systems (CPSs) are open and interconnected embedded systems that control or interact with physical processes. Failures in CPSs can lead to loss of production time, damage to the equipment and environment, or loss of life, meaning that dependability and resilience are key properties for their design. However, existing fault tolerance and safety approaches are inadequate for complex, networked and dynamic CPSs. Service-orientation, on the other hand, is generally considered to be a robust architectural style, but there is a limited amount of research on fault tolerance of service-oriented architecture (SOA), especially on distributed real-time systems. We propose an approach that utilizes the loosely coupled nature of services to implement fault tolerance using a middleware-based real-time SOA (RTSOA) for CPSs. The approach, based on the concepts of fault isolation and recovery at the service level, is empirically evaluated using a demanding bilateral teleoperation (remote handling) application. The empirical evaluation demonstrates that RTSOA supports real-time fault detection and recovery, use of services as a unit of fault isolation, and it provides capability to implement fault tolerance patterns flexibly and without significant overhead.

Guest editorial notes for selected papers from ICEBE 2011

This special issue presents the extended and revised papers selected from the IEEE 2011 International Conference on e-Business Engineering (ICEBE 2011), which was held in Beijing, China. The ICEBE conference is a prestigious conference which is initiated from 2003 by the IEEE Computer Society Technical Committee on Business Informatics and Systems (TCBIS). Among the 119 submissions to ICEBE 2011, 26 papers were accepted as long papers. The accepted papers represent 18 countries and regions around the world, and five continents, including Africa, Europe, America, Australia andAsia. After the conference, a few highly ranked papers were invited to submit their extensions to the Springer Journal . After two more rounds of rigorous reviews by prestigious researchers, only three papers have been accepted for publication in this special issue. The selected papers cover the key underlying techniques of building e-business systems, from the service-oriented architecture (SOA) to data mining tools. In the paper titled “Real-time Service Process Admission Control with Schedule Reorganization,” Sen Zhou and Kwei-Jay Lin addressed the problem of resource reservation for applications using the real-time service-oriented architecture (RT-SOA) paradigm. In “QoSAggregation for ServiceOrchestrationsBased on Workflow Pattern Rules and MCDMMethod: Evaluation at Design Time and Runtime,” Nabil Fakhfakh et al. proposed an approach to determine the satisfaction degree corresponding to the QoS of service-based applications, targeting both design time and runtime aggregation of QoS. In “Data Mining for Unemployment Rate Prediction using Search Engine Query Data,” Wei Xu et al. proposed a data mining

Real-time service process admission control with schedule reorganization

This paper addresses the problem of resource reservation for applications using the real-time service-oriented architecture paradigm. Real-time services must be completed by their deadlines. They can be scheduled anywhere within an execution interval. Some services have a large execution interval which gives them more flexibility during admission control. However, the conventional approach for real-time process scheduling is to reserve a fixed schedule on the first come, first served basis and thus does not take advantage of this flexibility. In this paper, a reorganization algorithm is presented to relocate existing reservations in order to accommodate new requests that have less flexibility. For service process reservations, intermediate deadlines may also be adjusted to further increase the flexibility of service reservations. Simulation results show that reorganization can greatly enhance the acceptance ratio of real-time requests in most situations.

Guest editorial: special section on real-time service-oriented architecture and applications

Guest editorial: special section on real-time service-oriented architecture and applications

Toward effective service composition for real-time SOA-based systems

Many application domains are increasingly leveraging service-oriented architecture (SOA) techniques to facilitate rapid system deployment. Many of these applications are time-critical and, hence, real-time assurance is an essential step in the service composition process. However, there are gaps in existing service composition techniques for real-time systems. First, admission control is an essential technique to assure the time bound for service execution, but most of the service composition techniques for real-time systems do not take admission control into account. A service may be selected for a workflow during the composition phase, but then during the grounding phase, the concrete service may not be able to admit the workload. Thus, the entire composition process may have to be repeated. Second, communication time is an important factor in real-time SOA, but most of the existing works do not consider how to obtain the communication latencies between services during the composition phase. It is clear that maintaining a full table of communication latencies for all pairs of services is infeasible. Obtaining communication latencies between candidate services during the composition phase can also be costly, since many candidate services may not be used for grounding. Thus, some mechanism is needed for estimating the communication latency for composite services. In this paper, we propose a three-phase composition approach to address the above issues. In this approach, we first use a highly efficient but moderately accurate algorithm to eliminate most of the candidate compositions based on estimated communication latencies and assured service response latency. Then, a more accurate timing prediction is performed on a small number of selected compositions in the second phase based on confirmed admission and actual communication latency. In the third phase, specific concrete services are selected for grounding, and admissions are actually performed. The approach is scalable and can effectively achieve service composition for satisfying real-time requirements. Experimental studies show that the three-phase approach does improve the effectiveness and time for service composition in SOA real-time systems. In order to support the new composition approach, it is necessary to effectively specify the needed information. In this paper, we also present the specification model for timing-related information and the extension of OWL-S to support this specification model.

Event-driven modeling and testing of real-time web services

A service-oriented architecture (SOA) for web applications is often implemented using web services (WSs) and consists of different operations the executions of which are perceived as events. The order and time-appropriateness of occurrences of these events play a vital role for the proper functioning of a real-time SOA. This paper presents an event-based approach to modeling and testing of functional behavior of WSs by event sequence graphs (ESG). Nodes of an ESG represent events, e.g., “request” or “response”, and arcs give the sequence of these events. For representing parameter values, e.g., for time-out of operation calls, ESG are augmented by decision tables. A case study carried out on a commercial web system with SOA validates the approach and analyzes its characteristic issues. The novelty of the approach stems from (i) its simplicity and lucidity in representing complex real-time web applications based on WSs in SOA, and (ii) its modeling that considers also testing and thus enables a comfortable fault management leading to a holistic view.

RT-Llama

Service-oriented architectures (SOA) are being adopted in a variety of industries. Some of them must support real-time activities. In this article, the authors present RT-Llama, a novel architecture for real-time SOA to support predictability in business processes. Upon receiving a user-requested process and deadline, our proposed architecture can reserve resources in advance for each service in the process to ensure it meets its end-to-end deadline. The architecture contains global resource management and business process composition components. They also create a real-time enterprise middleware that manages utilization of local resources by using efficient data structures and handles service requests via reserved CPU bandwidth. They demonstrate that RT-Llama’s reservation components are both effective and adaptable to dynamic real-time environments.