Resilient Critical Infrastructure Management using Service Oriented Architecture

Abstract—The SERSCIS project aims to support the use of interconnected systems of services in Critical Infrastructure (CI) applications. The problem of system interconnectedness is aptly demonstrated by ‘Airport Collaborative Decision Making’ (ACDM). Failure or underperformance of any of the interlinked ICT systems may compromise the ability of airports to plan their use of resources to sustain high levels of air traffic, or to provide accurate aircraft movement forecasts to the wider European air traffic management systems. The proposed solution is to introduce further SERSCIS ICT components to manage dependability and interdependency. These use semantic models of the critical infrastructure, including its ICT services, to identify faults and potential risks and to increase human awareness of them. Semantics allows information and services to be described in such a way that makes them understandable to computers. Thus when a failure (or a threat of failure) is detected, SERSCIS components can take action to manage the consequences, including changing the interdependency relationships between services. In some cases, the components will be able to take action autonomously — e.g. to manage ‘local’ issues such as the allocation of CPU time to maintain service performance, or the selection of services where there are redundant sources available. In other cases the components will alert human operators so they can take action instead. The goal of this paper is to describe a Service Oriented Architecture (SOA) that can be used to address the management of ICT components and interdependencies in critical infrastructure systems. Index Terms—resilience; QoS; SOA; critical infrastructure, SLA

Dynamic Multilevel Workflow Management Concept for Industrial IoT Systems

Workflow management is implemented in manufacturing at many levels. The nature of processes variesat each level, hindering the use of a standard modeling orimplementation solution. The creation of a flexible workflow management framework that overarches the heterogeneous business process levels is challenging. Still, one of the promisesof the Industry 4.0 initiative is precisely this: to provideeasy-to-use models and solutions that enable efficient execution of enterprise targets. By addressing this challenge, this articleproposes a workflow execution model that integrates information and control flows of these levels while keeping their hierarchy. The overall model builds on the business process model andnotation (BPMN) for modeling at the enterprise level and recipemodeling based on colored Petri net (CPN) at the production level. Models produced with both alternatives are implemented and executed in a framework supported by an enterprise servicebus (ESB). Loosely coupled, late-bound system elements are connected through the arrowhead framework, which is builtupon the service-oriented architecture (SOA) concept. To proveits feasibility, this article presents the practical application ofthe model via an automotive production scenario

Discover, Reuse and Share Knowledge on Service Oriented Architectures

Current Semantic Web frameworks provide a complete infrastructure to manage ontologies schemes easing information retrieval with inference support. Ideally, the use of their frameworks should be transparent and decoupled, avoiding direct dependencies either on the application logic or on the ontology language. Besides there are different logic models used by ontology languages (OWL- Description Logic, OpenCyc-FOL, ...) and query languages (RDQL, SPARQL, OWLQL, nRQL, etc..). These facts show integration and interoperability tasks between ontologies and applications are tedious on currently systems. This research provides a general ESB service engine design based on JBI that enables ontology query and reasoning capabilities thought an Enterprise Service Bus. An early prototype that shows how works our research ideas has been developed

Fault management of web services

The use of service-oriented (SO) distributed systems is increasing. Within service orientation web services (WS) are the de facto standard for implementing service-oriented systems. The consumers of WS want to get uninterrupted and reliable service from the service providers. But WS providers cannot always provide services in the expected level due to faults and failures in the system. As a result the fault management of these systems is becoming crucial. This work presents a distributed event-driven architecture for fault management of Web Services. According to the architecture the managed WS report different events to the event databases. From event databases these events are sent to the event processors. The event processors are distributed over the network. They process the events, detect fault scenarios in the event stream and manage faults in the WS

A Classification of BPEL Extensions

The Business Process Execution Language (BPEL) has emerged as de-facto standard for business processes implementation. This language is designed to be extensible for including additional valuable features in a standardized manner. There are a number of BPEL extensions available. They are, however, neither classified nor evaluated with respect to their compliance to the BPEL standard. This article fills this gap by providing a framework for classifying BPEL extensions, a classification of existing extensions, and a guideline for designing BPEL extensions

On-demand provisioning of services

Workflows and service oriented computing (SOC) are an integral part of today's business scenarios. The SimTech project aims to leverage these proven technologies in the context of scientific research. Yet, this field of eScience has different requirements on SOC than their business counterparts. One of these differences is, that services and resources needed by scientists are commonly only required for very specific amounts of time and do not need to follow the always-on principle of traditional SOC. Thus, a means is necessary to make services and resources available when required and also free them again as soon as they are no longer needed. As a solution to utilize SOC in eScience scenarios, SimTech promotes the use of Cloud Technologies to enable the on-demand provisioning of services and their necessary infrastructure. This diploma thesis is focused on describing different architectural concepts and designs that enable the on-demand provisioning of services and their underlying infrastructure and middleware. These designs and concepts aim to strike a middle ground between abstract high-level architectures and very low-level architectures that focus solely on software specifics. The concepts have been designed in context of a Scientific Workflow Management System. A prototypical implementation that demonstrates the developed concepts concludes this thesis

Influencing the run-time behaviour of complex services using contexts

Service oriented architecture (SOA) and web services make it possible to construct rich and complex distributed systems which operate at internet scales. However, the underlying design principles of SOA can lead to management problems for processes over web services. This thesis identifies several potential problems with the management of processes over web services, and proposes the use of explicit context as a possible solution. The available options are explored, and the WS-Context specification is implemented and evaluated. The SOA design principles of loose coupling, interaction at an interface, autonomy, and composablity can lead to management problems for processes over web services. Processes over web services where one composite service invokes other composite services which in turn invoke other composite services can lead to complex invocation trees. These invocation trees may be different at different times due to the shifting effect of loose coupling, as new services are swapped in to replace those in previous invocations. In such an environment how well can we define the interface of the top level service in a static document such as a WSDL? Because there is a separation between the ultimate service consumer, and the ultimate service provider how can the service consumer correctly assign fault when a service fails? When concurrency is used, and encouraged, how can we deal with the inevitable race conditions and deadlock? In distributed systems where portions of processes execute on systems beyond our organizational control, how can we pause, or kill these processes? Many of these systems model long-running business processes. How do we communicate changes in process requirements? The use of an explicit context is a potential solution to these types of problems. The abstraction context provides an environment in which the process participants can describe their requirements, query those of other process participants, and react to changes in the environment. A sample context server, based on the WS-Context specification, was implemented using the Erlang language. The sample context server provides the basic operations required to manage and store contextual information about a process. The sample context server was evaluated to determine the cost of employing a context as part of a web service based software system. The performance of the sample server was also evaluated. Test were conducted on the time costs of the basic operations of the context server, and they were found to have a constant time cost. The operations for getting and setting the contents of the context were found to have a time cost dependant on the size of the context. The cost of propagating the context along a chain of service invocations was tested and found to have an overhead which increased linearly with the length of the service invocation chain. The context server was stress tested using a closed loop test which simulated the interaction of a number of concurrent clients, and an open loop test which simulated bursts of arriving requests. The open loop testing showed that the context server could handle 75 concurrent clients. Beyond 75 concurrent clients, the response times of the context server began to slowly increase. The closed loop testing showed that the context server had a maximum throughput of 190 requests per second for bursts of 200 requests with an interarrival time of 4 milliseconds

JeroMF: A Software Development Framework for Building Distributed Applications Based on Microservices and JeroMQ

This report describes a project involving the design, implementation, and testing of a software development framework, called JeroMF, that can help developers create scalable distributed applications based on a microservice architecture and that uses JeroMQ (a native Java implementation of ZeroMQ) for message passing. JeroMF provides an execution framework and extensible components for implementing processes, services, communication channels, messages, communication statistics, and encryption. Applications built with JeroMF do not require a message broker or any other middleware processes. However, they may include an optional Service Registry that can facilitate for service discovery and secure communications. The Service Registry itself was implemented with JeroMF and is included as part of the JeroMF distribution. Thorough unit, integration and system test cases exist for every component of JeroMF. For validation, JeroMF was used to re-design and re-implement a distributed health-care application with 13 separate types of services and very strict security requirements