Event-driven Architecture Research Articles

Using a data-centric event-driven architecture approach in the integration of real-time systems at DTP2

Integration of heterogeneous and distributed systems is a challenging task, because they might be running on different platforms and written with different implementation languages by multiple organizations. Data-centricity and event-driven architecture (EDA) are concepts that help to implement versatile and well-scaling distributed systems.This paper focuses on the implementation of inter-subsystem communication in a prototype distributed remote handling control system developed at Divertor Test Platform 2 (DTP2). The control system consists of a variety of heterogeneous subsystems, including a client–server web application and hard real-time controllers. A standardized middleware solution (Data Distribution Services (DDS)) that supports a data-centric EDA approach is used to integrate the system.One of the greatest challenges in integrating a system with a data-centric EDA approach is in defining the global data space model. The selected middleware is currently only used for non-deterministic communication. For future application, we evaluated the performance of point-to-point communication with and without the presence of additional network load to ensure applicability to real-time systems. We found that, under certain limitations, the middleware can be used for soft real-time communication. Hard real-time use will require more validation with a more suitable environment.

An Event-Driven Platform for Agility Management of Crisis Response

This article aims at presenting a whole approach of Information System Interoperability management in a crisis management cell: a Mediation Information System (MIS) may be used to help the crisis cell partners to design, run and manage the workflows of the response to a crisis situation. The architecture of the MIS meets the needs of low coupling between the partners' Information System components and the need of agility for such a platform. It is based on Service Oriented Architecture (SOA) and Event-Driven Architecture (EDA) principles that are combined to the Complex Event Processing (CEP) principles. This should leads on the one hand to an easier orchestration, choreography and real-time monitoring of the workflows' activities, on the other hand to assume on-the-fly automated agility of the crisis response (considering agility as the ability of the processes to remain consistent with the response to the crisis).

A stepwise approach to developing staged applications

The staged event-driven architecture (SEDA) can be seen as a milestone as regards integration of threads and events in a single model. By decomposing applications into sets of multi-threaded stages connected by event queues, SEDA allows for the use of each concurrency model where most appropriate. Inside each SEDA stage, the number and scheduling policy of threads can be adjusted to enhance performance. SEDA lends itself to parallelization on multi-cores and is well suited for many high-volume data stream processing systems and highly concurrent event processing systems. In this paper, we propose an extension to the staged model that decouples application design from specific execution environments, encouraging a stepwise approach for designing concurrent applications, similar to Foster's PCAM methodology. We also present Leda, a platform that implements this extended model. In Leda, stages are defined purely by their role in application logic, with no concern for locality of execution, and are bound together through asynchronous communication channels, called connectors, to form a directed graph representing the flow of events inside the application. Decisions about the configuration of the application at execution time are delayed to later phases of the implementation process. Stages in the application graph can then be grouped to form clusters, and each cluster is mapped to an exclusive OS process, running on an arbitrary host. Finally, we discuss two example applications which we developed to evaluate the Leda platform.

The performance improvements of highly-concurrent grid-based server

Server performance is one of the critical activities in the data grid environment. A large number of applications require access to huge volumes of data from grid servers. In this case, efficient, scalable and robust grid server which can deal with large file transfer concurrent is needed. In this paper, we analyze the bottleneck of our grid servers and introduce user-space I/O scheduling, zero copy and event-driven architecture in our grid server to improve the servers’ performance. The user-space I/O scheduling can save almost 50% I/O time in a huge number of small files transfer. Grid servers can elimination CPU consumptions between kernel and user space by zero copy and cut 63% times for context switches. Event-driven architecture will save 30% CPU usage to reach the best performance by thread-driven architecture. Optimization method combination of these three above are used in our grid servers, the full-load throughput of our system is 30% more than traditional solutions and only 60% CPU consumed compared with traditional solutions.

Event Based Approach for Web Services Composition

The success of the Internet and the ongoing globalization led to a demand for new solutions to meet the requirements for ITsystems. The paradigm of service-oriented and event-driven architecture with fine grained and loosely coupled services tries to cope with those needs. Service Oriented Architecture (SOA) and Event Driven Architecture (EDA) are two acknowledged architectures for the development of business applications and information systems, which have evolved separately over the years. Today both architectures are acknowledged, but their synergy is not. There are numerous benefits of having an architecture that supports coexistence between operations and events, and composition of services based on operation invocation and event triggering. As part of our ongoing research work, we have tried to analyze in this paper, the basic design of Event based systems, issues that have to be addressed when event based approach is used for composing and coordinating web services. Then we have specified the techniques available that handle these issues, and gave a comparative study on these techniques. Finally we have attempted to sort out the unhandled/ partially handled issues that could be addressed as part of our research.

Event-driven agility of interoperability during the Run-time of collaborative processes

The modern business environment tends to involve a large network of heterogeneous people, devices and organizations that engage in collaborative processes among themselves. Given the nature of this type of collaboration and the high degree of interoperability between partner Information Systems, these processes need to be agile in order to respond to changes in context, which may occur at any time during the collaborative situation.The objective is to build a Mediation Information System (MIS), in support of collaborative situations, whose architecture must be (i) built to be relevant to the collaborative situation under consideration, (ii) more easily integrated into the existing systems, and (iii) sufficiently agile, through its awareness of the environment and of process events, and through the way it reacts to events detected as being relevant.To apply agility mechanisms, it is crucial to detect the significant events that will lead to a subsequent evolution of the situation (detection step). Event-Driven Architecture (EDA) is used to design the structure of the part of the system that is in charge of MIS agility. This architecture takes the events into account, manages them and, if needed, uses them to trigger the adaptation of the MIS.We have defined a means to monitor the evolution of the situation. If relevant changes are detected, and if the situation does not evolve in the expected way, an adaptation is proposed.It is concluded that the principles of detection and adaptation, combined with the responsiveness of the system (provided by the automation of transitions), and based on Event Driven Architecture principles, together provide the agility required for collaborative processes.

Overview of complex event processing technology and its application in logistics Internet of Things

Complex Event Processing(CEP) is currently an advanced analytical technology which deals with high velocity event streams in a real-time way and primarily gets applied in Event Driven Architecture(EDA) system domain.It is helpful to realize intelligent business in many applications.For the sake of reporting its research status,the paper introduced the basic meaning and salient feature of CEP,and proposed a system architecture model composed of nine parts.Afterwards,the main constituents of the model were reviewed in terms of key technology and its formalization.In order to illustrate how to use CEP in the logistic Internet of things,an application framework with CEP infiltrating in it was also proposed here.It can be concluded that CEP has many merits and can play an important role in application fields.Finally,the shortcomings of this research domain were pointed out and future works were discussed.The paper systematically analyzed the CEP technology in terms of theory and practice so as to further develop CEP technology.

事件驱动、面向服务的物联网服务提供方法

Internet of Things (IoT) seamlessly integrates the user domain, cyberspace and physical space domains, and realizes the dynamic human-machine-thing collaborations. In general, IoT applications often comprise the interactions of human activities, software services and physical entities spanning multiple service domains or organizations. An IoT application system often involves the aggregation of several distributed enterprise application systems. It builds a larger, composite system to collaboratively achieve a specific business goal. Most previous work only focuses on the interconnection and interoperability problems among different entities and enterprise application systems in a dynamic interaction environment. However, the problems of how to efficiently disseminate the sensing information among the information providers and consumers on-demand and how to dynamically coordinate the relevant enterprise services or business processes based on the occurred events from the real world still have not been comprehensively explored. To resolve these problems, we propose an EDSOAbased (Event-driven Service-oriented Architecture) IoT service provisioning approach which well integrates the advantages of EDA (Event-driven Architecture) and SOA (Service-oriented Architecture) in this paper. The combination of SOA and EDA can easily support the on-demand dissemination of sensing information and realize the event-driven dynamic service coordination cross domain. This proposed approach enhances the flexibility and responsiveness of IoT service systems, which allows these systems to respond dynamically, in real time, as events occur. Finally, we demonstrate its practicability by a deployed District Heating Control and Information Service System (DHCISS) application.

Automatic Audio and Video Event Recognition in an Intelligent Resource Management System

Event recognition systems have high potential to support crisis management and emergency response. For large-scale scenarios, however, the sheer amount of possible audio and video channels requires adequate processing of the material by automatic means. In this article, the authors focus on automatic audio and video event recognition, by means of detecting abnormalities both in train noise as well as surveillance videos, and by conducting automatic speech recognition on fire fighter communication. All components are integrated in an overall intelligent resource management system. The authors elaborate on the challenges expected from real life data and the solutions that the authors applied. The overall system, based on Event-Driven Service-Oriented Architecture, has been implemented and partly integrated into the end users' infrastructures. The system has been continuously running for more than two years, collecting data for research purposes.

A Low-Delay, Light-Weight Publish/Subscribe Architecture for Delay-Sensitive IOT Services

In order to build a low-latency and light-weight publish/subscribe (pub/sub) system for delay-sensitive IOT services, the authors propose an efficient and scalable broker architecture named Grid Quorum-based pub/sub (GQPS). As a key component in Event-Driven Service-Oriented Architecture (EDSOA) for IOT services, this architecture organizes multiple pub/sub brokers into a Quorum-based peer-to-peer topology for efficient topic searching. It also leverages a topic searching algorithm and a one-hop caching strategy to minimize the search latency. Light-weight RESTful interfaces make the authors’ GQPS more suitable for IOT services. Cost analysis and experimental study demonstrate that the GQPS achieves a significant performance gain in search satisfaction without compromising search cost. The authors apply the proposed GQPS in the District Heating Control and Information Service System in Beijing, China. This system validates the effectiveness of GQPS.

Towards pattern‐based architectures for event processing systems

SUMMARYRecently, event processing (EP) has gained considerable attention as an individual discipline in computer science. From a software engineering perspective, EP systems still lack the maturity of well‐established software architectures. For the development of industrial EP systems, generally accepted software architectures based on proven design patterns and principles are still missing. In this article, we introduce a catalog of design patterns that supports the development of event‐driven architectures (EDAs) and complex EP systems. The design principles originate from experiences reported in publications as well as from our own experiences in building EP systems with industrial and academic partners. We present several patterns on different layers of abstractions that define the overall structure as well as the building blocks for EP systems. Architectural patterns that determine the top‐level structure of an EDA can be distinguished from design patterns that specify the basic mechanisms of EP. The practical application of the catalog of patterns is described by the pattern‐based design of a sample EDA for a sensor‐based energy control system. Finally, we propose a coherent and general reference architecture for EP derived from the proposed patterns.Copyright © 2013 John Wiley & Sons, Ltd.

FPGA based wireless sensor node with customizable event-driven architecture

Abstract Abstract This article presents the design and implementation of modular customizable event-driven architecture with parallel execution capability for the first time with wireless sensor nodes using stand alone FPGA. This customizable event-driven architecture is based on modular generic event dispatchers and autonomous event handlers, which will help WSN application developers to quickly develop their applications by adding the required number of event dispatchers and event handlers as per the need of a WSN application. This architecture can handle multiple events in parallel, including high priority ones. Additionally, it provides non-preemptive operation which removes the timing uncertainty and overhead involved with interrupt-driven processor-based sensor node implementation, which is required in real-time wireless sensor networks (WSNs). Thus, higher computation power of FPGAs combined with the non-preemptive modular event-driven architecture with parallel execution capability enables a variety of new WSN applications and facilitates rapid prototyping of WSN applications. In this article, the performance of FPGA-based sensor device is compared with general purpose processor-based implementations of sensor devices. Results show that our FPGA-based implementation provides significant improvement in system efficiency measured in terms of clock cycle counts required for typical sensor network tasks such as packet transmission, relay and reception.

Active on-demand service method based on event-driven architecture for geospatial data retrieval

Timely on-demand access to geospatial data is necessary for environmental observation and disaster response. However, traditional service methods for acquiring geospatial data are inefficient and cumbersome, which is not beneficial for timely data acquisition. In these service methods, data are obtained and published by managers and are then left to users to discover and to retrieve them. To solve this problem, we propose an event-driven active on-demand data service method, for which a prototype based on sensor web technologies is demonstrated. First, we select a subset of observed properties as the attributes of an observation event of a data service system. Event-filtering technologies are then employed to find the data desired by users. Finally, the data that meet the subscription requirement are pushed to subscribers on time. The aims of the implementation of the method are to test the suitability of the observation and measurement (O&M) profile for Earth observation and OGC event pattern markup language (EML) specification. We determined the attributes of observation events according to the requirement of the data service and encoded observation event information using the OGC Observations and Measurements specification. We encoded the information under filtering conditions using the OGC Event Pattern Markup Language specification. We implemented a data service method that is based on event-driven architecture via a combination of some sensor web enablement services. Finally, we verified the feasibility of the method using MODIS data from the forest fires that occurred on February 7, 2009, in Victoria, Australia. The results show that the proposed method can achieve actively pushing the desired data to subscribers in the shortest possible time. O&M profiles for Earth observation and EML are suitable for the metadata encoding of observation events and the encoding of subscription information respectively. They match well for the data service in the system.

Staged event-driven architecture as a micro-architecture of distributed and pluginable crawling platform

There are many crawling systems available on the market but they are rather close systems dedicated for performing particular kind and class of tasks with predefined set of scope, strategy etc. In real life however there are meaningful groups of users (e.g. marketing, criminal or governmental analysts) requiring not just a yet another crawling system dedicated for performing predefined tasks. They need rather easy-to-use, user friendly all-in-one studio for not only executing and running internet robots and crawlers, but also for (graphical) (re)defining and (re)composing crawlers according to dynamically changing requirements and use-cases. To realize the above-mentioned idea, Cassiopeia framework has been designed and developed. One has to remember, however, that enormous size and unimaginable structural complexity of WWW network are the reasons that, from a technical and architectural point of view, developing effective internet robots – and the more so developing a framework supporting graphical robots’ composition – becomes a really challenging task. The crucial aspect in the context of crawling efficiency and scalability is concurrency model applied. There are two the most typical concurrency management models i.e. classical concurrency based on the pool of threads and processes and event-driven concurrency. None of them are ideal approaches. That is why, research on alternative models is still conducted to propose efficient and convenient architecture for concurrent and distributed applications. One of promising models is staged event-driven architecture mixing to some extent both of above mentioned classical approaches and providing some additional benefits such as splitting application into separate stages connected by events queues – what is interesting taking requirements about crawler (re)composition into account. The goal of this paper is to present the idea and the PoC implementation of Cassiopeia framework, with the special attention paid to its crucial architectural element i.e. design, implementation and applying of staged event-driven architecture being a micro-architecture of Cassiopeia’s agents i.e. its key computational and processing units

AN EVENT-DRIVEN ARCHITECTURE FOR INTEGRATING INFORMATION, PROCESSES AND SERVICES IN A PLASTIC TOYS SUPPLY CHAIN

In global supply chains, a multitude of public and private organizations collaborate to reach the collective goal of transporting goods from the seller to the buyer. Given the dynamicity of global supply chains it is hard to predict which information is needed by whom at which point in time which often causes service delivery delays. Integrating relevant information, processes and services prevents disruptions in the supply chain and deterioration in service provisioning caused by missing information required for processes that need to be executed to supply services. In this paper, an ontology-based, event-driven architecture is designed for integrating information, processes and services that acts as a mechanism to coordinate service delivery in a global supply chain. The architecture is evaluated in the context of a global supply chain of plastic toys. This illustrates how the events facilitated by the architecture enable the availability of information in time which positively influences the delivery of a barge planning service.

The XMOS Architecture and XS1 Chips

The XMOS architecture scales from real-time systems with a single multithreaded processor to systems with thousands of processors. Concurrent processing, communications, and I/O are supported by the instruction set of the XCORE processors and by the message-routing techniques and protocols in the XMOS interconnect. The event-driven architecture supports energy-efficient multicore and multichip systems in which cores are active only when needed.

Development of tsunami early warning systems and future challenges

Abstract. Fostered by and embedded in the general development of information and communications technology (ICT), the evolution of tsunami warning systems (TWS) shows a significant development from seismic-centred to multi-sensor system architectures using additional sensors (e.g. tide gauges and buoys) for the detection of tsunami waves in the ocean. Currently, the beginning implementation of regional tsunami warning infrastructures indicates a new phase in the development of TWS. A new generation of TWS should not only be able to realise multi-sensor monitoring for tsunami detection. Moreover, these systems have to be capable to form a collaborative communication infrastructure of distributed tsunami warning systems in order to implement regional, ocean-wide monitoring and warning strategies. In the context of the development of the German Indonesian Tsunami Early Warning System (GITEWS) and in the EU-funded FP6 project Distant Early Warning System (DEWS), a service platform for both sensor integration and warning dissemination has been newly developed and demonstrated. In particular, standards of the Open Geospatial Consortium (OGC) and the Organization for the Advancement of Structured Information Standards (OASIS) have been successfully incorporated. In the FP7 project Collaborative, Complex and Critical Decision-Support in Evolving Crises (TRIDEC), new developments in ICT (e.g. complex event processing (CEP) and event-driven architecture (EDA)) are used to extend the existing platform to realise a component-based technology framework for building distributed tsunami warning systems.

Design and Implement of Dynamic Context-Aware Monitoring System Based on OWL

Context-aware applications can sense and explore the context of production processes to provide proper and useful services to managers in workshop. The monitoring levels are partitioned and designed in this article. And the multi-level ontology model of materials is found which is expressed in the Web Ontology Language (i.e. OWL) as a ontology collection of describing places ages and events and associated properties among them. Within an intelligent monitoring system, dynamic adjusting algorithm of linking local coordination with global coordination for lacking parts is brought forward and dynamic coordination structure is put up based on event-driven architecture. Context-aware reactive behaviors can be expressed by using rules written in OWL Language, especially developed for context-aware applications.

A Cooperative Approach to Traffic Congestion Detection With Complex Event Processing and VANET

Currently, distributed traffic information systems have come up as one of the most important approaches for detecting traffic flow problems on a road. For that purpose, they usually make use of the location information that vehicles share among them through periodical messages that are transmitted across a vehicular ad hoc network (VANET). This paper puts forward an event-driven architecture (EDA) as a novel mechanism to get insight into VANET messages to detect different levels of traffic jams; furthermore, it also takes into account environmental data that come from external data sources, such as weather conditions. The proposed EDA has been developed through the complex-event-processing technology. Simulation tests show that the proposed mechanism can detect traffic congestions, which involve different numbers of lanes and lengths with short delay.

Redesign Distributed PLC Control Systems Using IEC 61499 Function Blocks

The IEC 61499 Function Block architecture is considered as the next generation of programmable control technology promoting distributed control in automation. In this paper, the redesign methodologies from the PLC control to the event-driven architecture of IEC 61499 function blocks are proposed. A general set of translation steps and mapping rules for redesigning applications from IEC 61131-3 PLC to IEC 61499 Function Blocks is provided. Three different redesign approaches are proposed: object-oriented conversion approach, object-oriented reuse approach, and class-oriented approach. These approaches are to be applied for different design styles of the source PLC code. The data handling efficiency of all approaches is investigated. An airport baggage handling system is chosen as the case study for the redesign process. The rules and limitations are summarized and guidelines for the redesign process are provided.