Intra-subnet Load Balancing in Distributed Workflow Management Systems

For enterprise-wide and cross-orgenizational process-oriented applications, the execution of workflows (WF) may generate a very high load. This load may affect WF servers as well as the underlying communication network. To improve system scalability, several approaches for distributed WF management have been proposed in the literature. They have in common that different partitions of a WF instance graph may be controlled by different WF servers from different subnets. The control over a particular WF instance, therefore, may be transferred from one WF server to another during run-time if this helps to reduce the overall communication load. Thus far, such distributed approaches assume that exactly one WF server resides in each subnet. A single server per subnet, however, may become overloaded. In this paper, we present and veify a novel approach for replicating WF servers in a distributed workflow management system. It enables an arbitraty and changeable distribution of the load to the WF servers of the same subnet, without requiring additional communication

Dynamic Change of Server Assignments in Distributed Workflow Management Systems

Workow management systems (WfMS) offer a promising approach for realizing process-oriented information systems. Central WfMS, with a single server controlling all workow (WF) instances, however, may become overloaded very soon. In the literature, therefore, many approaches suggest using a multi-server WfMS with distributed WF control. In such a distributed WfMS, the concrete WF server for the control of a particular WF activity is usually dened by an associated server assignment. Following such a partitioning approach, problems may occur if components (WF servers, subnets, or gateways) become overloaded or break down. As we know from other elds of computer science, a favorable approach to handle such cases may be to dynamically change hardware assignment. This corresponds to the dynamic change of server assignments in WfMS. This paper analyses to what extend this approach is reasonable in such situations

An Approach for Supporting Ad-hoc Modifications in Distributed Workflow Management Systems

Supporting enterprise-wide or even cross-organizational business processes is a characteristic challenge for any workflow management system (WfMS). Scalability at the presence of high loads as well as the capability to dynamically modify running workflow (WF) instances (e.g., to cope with exceptional situations) are essential requirements in this context. Should the latter one, in particular, not be met, the WfMS will not have the necessary flexibility to cover the wide range of process-oriented applications deployed in many organizations. Scalability and flexibility have, for the most part, been treated separately in the relevant literature thus far. Even though they are basic needs for a WfMS, the requirements related with them are totally different. To achieve satisfactory scalability, on the one hand, the system needs to be designed such that a workflow instance can be controlled by several WF servers that are as independent from each other as possible. Yet dynamic WF modifications, on the other hand, necessitate a (logical) central control instance which knows the current and global state of a WF instance. For the first time, this paper presents methods which allow ad-hoc modifications (e.g., to insert, delete, or shift steps) to be performed in a distributed WfMS; i.e., in a WfMS with partitioned WF execution graphs and distributed WF control. It is especially noteworthy that the system succeeds in realizing the full functionality as given in the central case while, at the same time, achieving extremely favorable behavior with respect to communication costs

ADEPT2 - Next Generation Process Management Technology

If current process management systems shall be applied to a broad spectrum of applications, they will have to be significantly improved with respect to their technological capabilities. In particular, in dynamic environments it must be possible to quickly implement and deploy new processes, to enable ad-hoc modifications of single process instances at runtime (e.g., to add, delete or shift process steps), and to support process schema evolution with instance migration, i.e., to propagate process schema changes to already running instances. These requirements must be met without affecting process consistency and by preserving the robustness of the process management system. In this paper we describe how these challenges have been addressed and solved in the ADEPT2 Process Management System. Our overall vision is to provide a next generation process management technology which can be used in a variety of application domains

Towards Hyperscale Process Management

Scalability of software systems has been a research topic for many years and is as relevant as ever with the dramatic increases in digitization of business operations and data. This relevance also applies to process management systems, most of which are currently incapable of scaling horizontally, i.e., over multiple servers. This paper discusses an approach towards hyperscale workflows, using a data-centric process engine to encapsulate data and process logic into objects, which can then be stored and concurrently manipulated independently from each other. As this allows for more concurrent operations, even within a single data-intensive process instance, we want to prove that an implementation of a hyperscale process engine is a feasible endeavor

Architectural and mobility management designs in internet-based infrastructure wireless mesh networks

Wireless mesh networks (WMNs) have recently emerged to be a cost-effective solution to support large-scale wireless Internet access. They have numerous ap- plications, such as broadband Internet access, building automation, and intelligent transportation systems. One research challenge for Internet-based WMNs is to design efficient mobility management techniques for mobile users to achieve seamless roam- ing. Mobility management includes handoff management and location management. The objective of this research is to design new handoff and location management techniques for Internet-based infrastructure WMNs. Handoff management enables a wireless network to maintain active connections as mobile users move into new service areas. Previous solutions on handoff manage- ment in infrastructure WMNs mainly focus on intra-gateway mobility. New handoff issues involved in inter-gateway mobility in WMNs have not been properly addressed. Hence, a new architectural design is proposed to facilitate inter-gateway handoff man- agement in infrastructure WMNs. The proposed architecture is designed to specifi- cally address the special handoff design challenges in Internet-based WMNs. It can facilitate parallel executions of handoffs from multiple layers, in conjunction with a data caching mechanism which guarantees minimum packet loss during handoffs. Based on the proposed architecture, a Quality of Service (QoS) handoff mechanism is also proposed to achieve QoS requirements for both handoff and existing traffic before and after handoffs in the inter-gateway WMN environment. Location management in wireless networks serves the purpose of tracking mobile users and locating them prior to establishing new communications. Existing location management solutions proposed for single-hop wireless networks cannot be directly applied to Internet-based WMNs. Hence, a dynamic location management framework in Internet-based WMNs is proposed that can guarantee the location management performance and also minimize the protocol overhead. In addition, a novel resilient location area design in Internet-based WMNs is also proposed. The formation of the location areas can adapt to the changes of both paging load and service load so that the tradeoff between paging overhead and mobile device power consumption can be balanced, and at the same time, the required QoS performance of existing traffic is maintained. Therefore, together with the proposed handoff management design, efficient mobility management can be realized in Internet-based infrastructure WMNs

Travelling Without Moving: Discovering Neighborhood Adjacencies

peer reviewedSince the early 2000's, the research community has explored many approaches to discover and study the Internet topology, designing both data collection mechanisms and models. In this paper, we introduce SAGE (Subnet AggrEgation), a new topology discovery tool that infers the hop-level graph of a target network from a single vantage point. SAGE relies on subnet-level data to build a directed acyclic graph of a network modeling how its (meshes of) routers, a.k.a. neighborhoods, are linked together. Using two groundtruth networks and measurements in the wild, we show SAGE accurately discovers links and is consistent with itself upon a change of vantage point. By mapping subnets to the discovered links, the directed acyclic graphs discovered by SAGE can be re-interpreted as bipartite graphs. Using data collected in the wild from both the PlanetLab testbed and the EdgeNet cluster, we demonstrate that such a model is a credible tool for studying computer networks

ADEPT Workflow Management System Flexible Support for Enterprise-Wide Business Processes - Tool Presentation -

In this tool presentation we give an overview of the ADEPT workflow management system (WfMS), which is one of the few available research prototypes dealingwith enterprise-wide, adaptive workflow (WF) management. ADEPT offers sophisticated modeling concepts and advanced features, like temporal constraint management, ad-hoc WF changes, WF schema evolution, synchronization of inter-workflow dependencies, and scalability. We sketch these features and describe how they have been realized within ADEPT. In addition, we show which tools and interfaces are offered to developers and users in this context. ADEPT follows a holistic approach, i.e., the described concepts have not been implemented in an isolated fashion only, but are treated in conjunction with each other by integrating them within one WfMS

Advancing Intra-operative Precision: Dynamic Data-Driven Non-Rigid Registration for Enhanced Brain Tumor Resection in Image-Guided Neurosurgery

During neurosurgery, medical images of the brain are used to locate tumors and critical structures, but brain tissue shifts make pre-operative images unreliable for accurate removal of tumors. Intra-operative imaging can track these deformations but is not a substitute for pre-operative data. To address this, we use Dynamic Data-Driven Non-Rigid Registration (NRR), a complex and time-consuming image processing operation that adjusts the pre-operative image data to account for intra-operative brain shift. Our review explores a specific NRR method for registering brain MRI during image-guided neurosurgery and examines various strategies for improving the accuracy and speed of the NRR method. We demonstrate that our implementation enables NRR results to be delivered within clinical time constraints while leveraging Distributed Computing and Machine Learning to enhance registration accuracy by identifying optimal parameters for the NRR method. Additionally, we highlight challenges associated with its use in the operating room

Machine Learning-Powered Management Architectures for Edge Services in 5G Networks

L'abstract è presente nell'allegato / the abstract is in the attachmen