Krzysztof Juszczyszyn

Service Composition in Knowledge-based SOA Systems

In this paper, we present the solution of the problem of Service Composition in Knowledge-based SOA (Service Oriented Architecture) Systems. SOA based systems are built of services - atomic or complex ones. Each service may have a different functional and non-functional description. The methods how to retrieve atomic service and compose complex services according to the user’s needs are discussed here.

Agent-Based approach for distributed intrusion detection system design

The aim of this paper is to propose an architecture of distributed Intrusion Detection System (IDS). It is assumed that IDS system will detect and track dissemination and activity of the Internet worms. A general architecture for such a distributed multiagent system is proposed and the tasks, techniques and algorithms to be used are sketched.

Link Prediction Based on Subgraph Evolution in Dynamic Social Networks

We propose a new method for characterizing the dynamics of complex networks with its application to the link prediction problem. Our approach is based on the discovery of network sub graphs (in this study: triads of nodes) and measuring their transitions during network evolution. We define the Triad Transition Matrix (TTM) containing the probabilities of transitions between triads found in the network, then we show how it can help to discover and quantify the dynamic patterns of network evolution. We also propose the application of TTM to link prediction with an algorithm (called TTM-predictor) which shows good performance, especially for sparse networks analyzed in short time scales. The future applications and research directions of our approach are also proposed and discussed.

Local Topology of Social Network Based on Motif Analysis

Network motifs --- small subgraphs that reflect local topology can be used to discover general profile and properties of the network. Analysis of motifs for the large social networks derived from email communication is presented in the paper. The distribution of motifs in all analyzed real social networks is very similar one another and can be treated as the network fingerprint. This property is most distinctive for stronger human relationships.

Supporting content, context and user awareness in future internet applications

We show how the applications utilizing a Future Internet architecture can benefit from its features like quality of service (QoS) provisioning and resources reservation.We demonstrate, how proposed applications address content, context and user awareness basing on the underlying Next Generation Network (NGN) infrastructure and how it can be used to host service-based applications.

Verifying enterprise's mandatory access control policies with coloured Petri nets

The paper addresses important problems met when implementing mandatory access control policies in complex distributed systems (e.g. enterprise networks). The role of formal security models is also presented and the properties of the model suitable for systems under consideration are defined. Then a formal security model, Secure Coloured Petri - using coloured Petri nets semantics - is proposed. It is shown how the enterprise security management system may take advantage of the proposed models properties. Application of coloured Petri nets analysis and construction methods to information flow security analysis is also proposed and discussed.

Creation and growth of online social network

Social networks are an example of complex systems consisting of nodes that can interact with each other and based on these activities the social relations are defined. The dynamics and evolution of social networks are very interesting but at the same time very challenging areas of research. In this paper the formation and growth of one of such structures extracted from data about human activities within online social networking system is investigated. Dynamics of both local and global characteristics are studied. Analysis of the dynamics of the network growth showed that it changes over time—from random process to power-law growth. The phase transition between those two is clearly visible. In general, node degree distribution can be described as the scale-free but it does not emerge straight from the beginning. Social networks are known to feature high clustering coefficient and friend-of-a-friend phenomenon. This research has revealed that in online social network, although the clustering coefficient grows over time, it is lower than expected. Also the friend-of-a-friend phenomenon is missing. On the other hand, the length of the shortest paths is small starting from the beginning of the network existence so the small-world phenomenon is present. The unique element of the presented study is that the data, from which the online social network was extracted, represents interactions between users from the beginning of the social networking site existence. The system, from which the data was obtained, enables users to interact using different communication channels and it gives additional opportunity to investigate multi-relational character of human relations.

Personalized Ontology-Based Recommender Systems for Multimedia Objects

A framework for recommendation of multimedia objects based on processing of individual ontologies is proposed in the chapter. The recommendation process takes into account similarities calculated both between objects’ and users’ ontologies, which reflect the social and semantic features existing in the system. The ontologies, which are close to the current context, provide a list of suggestions presented to the user. Each user in the system possesses its own Personal Agent that performs all necessary online tasks. Personal Agents co-operate each other and enrich lists of possible recommendations. The system was developed for the use inthe Flickr multimedia sharing system.

Smart work workbench; integrated tool for IT services planning, management, execution and evaluation

Smart Service Workbench (SSW) is an integrated tool devoted to support business processes in distributed IT environment based on Service Oriented Architecture (SOA) paradigm. The tools scope of functionalities is divided into modules that cover the whole process starting from the arrival of service request and ending with a return results of request. The latter is assumed to be a service composed of well-defined components available in predefined and staging repository. The tools modules are responsible for requirements analysis, services choice or service composition, communication and computational resources allocation in distributed environment as well as for resources utilization monitoring to services quality and security evaluation purposes.

Molecular dynamics modelling of the temporal changes in complex networks

The dynamic of complex social networks is nowadays one of the research areas of growing importance. The knowledge about the temporal changes of the network topology and characteristics is crucial in networked communication systems in which accurate predictions are important. In this paper a physics-inspired method to track the changes within complex social network is proposed. This method is based on the dynamic molecular modelling technique used in physics for simulation of large sets of interacting particles. The data for the conducted research was derived from e-mail communication within big company (Wroclaw University of Technology). From this information the social network of employees was extracted. The created social network was utilized to evaluate the methodology of social network dynamics modelling proposed by authors.