International Journal of Cooperative Information Systems

Lightweight authentication is one of the solutions proposed in order to reduce the time required for authentication during vertical handoff across heterogeneous networks. Reducing the handoff latency is considered to be a challenging issue. It arises when a user requires maintaining its service continuity while traveling across heterogeneous networks. For example, a mobile user may change access networks while being engaged in different scenarios, such as browsing Internet, using real-time applications or collaborating in cooperative information systems. Delay in the vertical handoff creates many problems, i.e. packet loss, service interruption, security problems, etc. Fast and lightweight authentication schemes are always tempted in such application domains because of many benefits, for instance seamless and efficient handoff, service continuity, guaranteed quality of service (QoS) and suitability for real-time applications while maintaining security. Various techniques have been proposed in this domain to reduce authentication delay. However, these methods do not fully address all the issues in the problem domain; for example, these methods have deficiencies in terms of security, monetary cost, signaling cost and packet latency. In this paper, a comparative study of different lightweight authentication methods is presented but the main focus of this work is one of the different implementations. An overview of major problems and their solutions are presented along with their strengths and limitations. Different emerging research areas are also presented in the domain of lightweight authentication in the vertical handoff.

On-the-fly data integration, i.e. at query time, happens mostly in tightly coupled, homogeneous environments where the partitioning of the data can be controlled or is known in advance. During the process of data fusion, the information is homogenized and data inconsistencies are hidden from the application. Beyond this, we propose in this paper the Nexus metadata model and a processing approach that support on-the-fly data integration in a loosely coupled federation of autonomous data providers, thereby advancing the status quo in terms of flexibility and expressive power. It is able to represent data and schema inconsistencies like multi-valued attributes and multi-typed objects. In an open environment, this best suites the application needs where the data processing infrastructure is not able to decide which attribute value is correct. The Nexus metadata model provides the foundation for integration schemata that are specific to a given application domain. The corresponding processing model provides four complementary query semantics in order to account for the subtleties of multi-valued and missing attributes. In this paper we show that this query semantics is sound, easy to implement, and it builds upon existing query processing techniques. Thus the Nexus metadata model provides a unique level of flexibility for on-the-fly data integration.

In this paper, a novel business process engineering method based on quality assessment is proposed. In the proposed method, a goal model is used to estimate the operational costs of business processes. Goals scenarios in the goal model of desired information systems are applied as a basis for estimating the design cost. Qualities of business requirements models and business process models are also estimated. Based on the quality metrics, the process of business process modeling is examined. Then, using XOR operator in the goal model, a simple and direct mapping of the goal model to the business process model is introduced. Common activities in the business process model are further factored and summarized using pre- and post-factoring operations. The proposed business process modeling method is language-independent. An ICT office in Mazandaran Power Distribution Company is used as a case study to exemplify QABPEM. Our evaluation results demonstrates the capability of the proposed method compared with the existing ones.