Michał Sajkowski

Modeling the process of human body iron homeostasis using a variant of timed Petri nets

The body iron homeostasis is one of the most important processes in the human body. This complex process is not fully understood and until recently only some parts of it have been described in the literature. In our recent papers the main part of the process has been described and a model based on Petri net theory has been proposed. However, in this model any time dependencies occurring in the biochemical process have not been taken into account. In the present paper the model is enriched in the way that durations of biochemical reactions composing this process have been included into the model. A variant of Petri net where with each place a time interval is associated has been used in order to describe these dependencies. The time interval associated with a place corresponds to a time lag of biochemical conditions which must be fulfilled in order to enable a biochemical reaction to start.

Dependability Infrastructure for SOA Applications

This chapter describes two tools for improving dependability of SOA-based applications: ReSP (Reliable SOA Platform) and DyMST (Dynamic Management SOA Toolkit). ReSP is a set of modules to improve dependability in respect to availability and reliability, and to some extent safety. It is comprised of the mechanisms of reliable group communication, replication, recovery, and transaction processing. DyMST is a set of components for failure detection, monitoring and autonomic management, and distributed security policy enforcement. In order to show the dependability aspects of real applications and usage of these tools, two case studies from the medical healthcare domain are presented: Healthcare Integration Platform for the exchange of patients’ medical data among various healthcare units, and Medical Event, and Data Registering Platform for daily work improvement of medical staff.

MDL: metrics definition language

The paper presents Metrics Definition Language (MDL), a new format for metric definition. MDL is a flexible grammar based language, which clearly separates the idea of a data source from a metric. Hence, MDL provides ways to define complex metrics that can be defined over many data sources or even other metrics. It also supports basic mathematical operations, that can be used to define metric aggregations and transformations. The language is human readable, universal and data format agnostic. It can be easily used with every monitoring system.

Detection of livelocks in communication protocols by means of a polygon time structure

As has been shown, the polygon time structure overcomes the main limitations of the interval time structure, and allows one to verify communication protocols, in which the explicit concurrency of both competing and supporting events is considered. The authors apply the polygon time structure to the verification of dynamic properties (like livelocks) of a simple protocol. As a result, they show that an application of the previously used interval time structure may lead to the evaluation of a protocol as incorrect, while it is livelock free.