4,146 research outputs found
Extending Eventually Consistent Cloud Databases for Enforcing Numeric Invariants
Geo-replicated databases often operate under the principle of eventual
consistency to offer high-availability with low latency on a simple key/value
store abstraction. Recently, some have adopted commutative data types to
provide seamless reconciliation for special purpose data types, such as
counters. Despite this, the inability to enforce numeric invariants across all
replicas still remains a key shortcoming of relying on the limited guarantees
of eventual consistency storage. We present a new replicated data type, called
bounded counter, which adds support for numeric invariants to eventually
consistent geo-replicated databases. We describe how this can be implemented on
top of existing cloud stores without modifying them, using Riak as an example.
Our approach adapts ideas from escrow transactions to devise a solution that is
decentralized, fault-tolerant and fast. Our evaluation shows much lower latency
and better scalability than the traditional approach of using strong
consistency to enforce numeric invariants, thus alleviating the tension between
consistency and availability
A Multiagent System for the Reliable Execution of Automatically Composed Ad-hoc Processes
This article presents an architecture to automatically create ad-hoc processes for complex value-added services and to execute them in a reliable way. The uniqueness of ad-hoc processes is to support users not only in standardized situations like traditional workflows do, but also in unique non-recurring situations. Based on user requirements, a service composition engine generates such ad-hoc processes, which integrate individual services in order to provide the desired functionality. Our infrastructure executes ad-hoc processes by transactional agents in a peer-to-peer style. The process execution is thereby performed under transactional guarantees. Moreover, the service composition engine is used to re-plan in the case of execution failure
Elastic Business Process Management: State of the Art and Open Challenges for BPM in the Cloud
With the advent of cloud computing, organizations are nowadays able to react
rapidly to changing demands for computational resources. Not only individual
applications can be hosted on virtual cloud infrastructures, but also complete
business processes. This allows the realization of so-called elastic processes,
i.e., processes which are carried out using elastic cloud resources. Despite
the manifold benefits of elastic processes, there is still a lack of solutions
supporting them.
In this paper, we identify the state of the art of elastic Business Process
Management with a focus on infrastructural challenges. We conceptualize an
architecture for an elastic Business Process Management System and discuss
existing work on scheduling, resource allocation, monitoring, decentralized
coordination, and state management for elastic processes. Furthermore, we
present two representative elastic Business Process Management Systems which
are intended to counter these challenges. Based on our findings, we identify
open issues and outline possible research directions for the realization of
elastic processes and elastic Business Process Management.Comment: Please cite as: S. Schulte, C. Janiesch, S. Venugopal, I. Weber, and
P. Hoenisch (2015). Elastic Business Process Management: State of the Art and
Open Challenges for BPM in the Cloud. Future Generation Computer Systems,
Volume NN, Number N, NN-NN., http://dx.doi.org/10.1016/j.future.2014.09.00
The Evolution of an Architectural Paradigm - Using Blockchain to Build a Cross-Organizational Enterprise Service Bus
Cross-organizational collaboration and the exchange of process data are indispensable for many processes in federally organized governments. Conventional IT solutions, such as cross-organizational workflow management systems, address these requirements through centralized process management and architectures. However, such centralization is difficult and often undesirable in federal contexts. One alternative solution that emphasizes decentralized process management and a decentralized architecture is the blockchain solution of Germany’s Federal Office for Migration and Refugees. Here, we investigate the architecture of this solution and examine how it addresses the requirements of federal contexts. We find that the solution’s architecture resembles an improvement and cross-organizational adaption of an old architectural paradigm, the enterprise service bus
Governance in the Blockchain Economy: A Framework and Research Agenda
Blockchain technology is often referred to as a groundbreaking innovation and the harbinger of a new economic era. Blockchains may be capable of engendering a new type of economic system: the blockchain economy. In the blockchain economy, agreed-upon transactions would be enforced autonomously, following rules defined by smart contracts. The blockchain economy would manifest itself in a new form of organizational design—decentralized autonomous organizations (DAO)—which are organizations with governance rules specified in the blockchain. We discuss the blockchain economy along dimensions defined in the IT governance literature: decision rights, accountability, and incentives. Our case study of a DAO illustrates that governance in the blockchain economy may depart radically from established notions of governance. Using the three governance dimensions, we propose a novel IT governance framework and a research agenda for governance in the blockchain economy. We challenge common assumptions in the blockchain discourse, and propose promising information systems research related to these assumptions
Transactional Agents for Pervasive Computing
Pervasive computing enables seamless integration of computing technology into everyday life to make upto- date information and services proactively available to the users based on their needs and behaviors. We aim to develop a transaction management scheme as a pertinent component for such environment supported by either structured or ad hoc networks. We propose Transactional Agents for Pervasive COmputing (TAPCO), which utilizes a dynamic hierarchical meta data structure that captures the semantic contents of the underlying heterogeneous data sources. Mobile agents process the transactions collaboratively, to preserve ACID properties without violating local autonomy of the data sources. TAPCO is simulated and compared against Decentralized Serialization Graph Testing (DSGT) protocol. The results show that TAPCO outperforms DSGT in several ways. In contrast to DSGT that did not consider local transactions, TAPCO supports both local and global transactions without violating the local autonomy
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