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Astract: Enterprise Resource Planning (ERP) systems are nowadays adapted to the company-specific requirements by customization. Whereas smaller and general feature changes are performed quickly by parameterization, changes of a company's business activities may lead to enormous changes in the system's code. To overcome this problem, we introduce an approach of a flexible ERP system which can be adapted by specific business models for each individual company/tenant by using model engineering techniques. Our approach REAlist is built on top of a generic data structure based on the Resource Event Agent (REA) business modeling ontology and provided as a cloud based service. Business models for each company are described by a domain specific language called the REA-DSL. REAlist enables companies to incorporate business activity changes quickly and without extensive code changes.

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Astract: The implementation of a domain agnostic software system (such as an enterprise resource planning system or a trading information system) based on the REA model requires a generic, yet highly adaptable software architecture. Building on top of well established academic findings and proposals regarding the REA model we are proposing a software model building on two main concepts: fragments and declarations. Together they establish a single, exible, extendible class hierarchy implemented purely on a database layer. Fragments and declarations are implemented as associative arrays that are enriched with metadata, providing clear access to attributes and their meta information. The system's exibility is drastically increased by enabling the multi-typification of REA entities.

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Astract: Sophisticated business rule engines provide a way to enable users with a non-software-engineering background to take action during the runtime of e.g. an enterprise information system: rules for customers can be defined, based on the turnover realized through them. The REA accounting model defines a concept for the modeling and excecution of business models, yet it does not go into detail how to implement and integrate business rules. We propose the integration of a proven business rule engine in contrast to the definition of a REA specific rule language or model by defining a set of anchor points into which specific business rules can be hooked that are fired when these anchor points are reached.

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Astract: The REA business model language is an established vehicle (i) to model businesses in terms of domain specific value chains and their key concepts and (ii) to capture business data in terms of accounting artefacts. REA has evolved into a specification that could drive web shops, enterprise/trading information systems, enterprise resource planning systems, etc. Such systems require support for sophisticated business rules in order to decouple business logic from application logic. In this work we present a framework for structural integration of business rules into REA business models.

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Astract: E-marketplaces on the World Wide Web are information and transaction silos, which in the general case don't allow transactions across their boundaries. The consequence is that the Web, often termed the global marketplace, is fragmented along the dimensions of geography, content domain, supply or demand, user base, and many more. This fragmentation makes it inefficient to buy and sell commodities on the Web. We propose a framework that serves as a foundation for a distributed, de-centralized e-marketplace on top of the Web, making boundaries between existing systems disappear from the user's perspective. The framework standardizes the creation and description of objects that represent supply and demand. In addition to this, it allows for independent matching services to connect objects suitable for a transaction and it defines protocols for the message exchange between such objects.