2019, Tom 27 Nr 1

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http://hdl.handle.net/11652/3830

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  • Pozycja
    Linguistic Summaries of Graph Databases in Customer Relationship Management (CRM)
    (Wydawnictwo Politechniki Łódzkiej, 2019) Bartczak, Monika; Niewiadomski, Adam
    The paper concentrates on data models that differ from the traditional relational one by Codd (1970). In particular, we are interested in processing graph databases (graph datasets) without any pre-configured structure, in which graph nodes may represent different objects and graph edges – relations between them. In this approach, the linguistic summarization methods for graph datasets are introduced, and differences for these methods with respect to traditional relational approach are shown, commented and improved in comparison to the preceding proposition (Strobin, Niewiadomski, 2016). The novelty of the paper is mostly the new form for summaries: Multi-Subject linguistic summaries of graph databases, previously introduced for relational databases (Superson, 2018).
  • Pozycja
    Modelling Heat Flow in a Heat Storage System with the Use of the Finite Volume Method
    (Wydawnictwo Politechniki Łódzkiej, 2019) Sobieski, Wojciech
    Non-stationary heat flow was analysed in a heat storage system comprising a flat multilayer structure with different parameters and thickness. Concrete was the heat storage material, and water was the transfer medium responsible for supplying and evacuating heat from the storage medium. It was assumed that the modelled heat storage system may be powered by a solar thermal collector. Data were collected over a period of 24 hours, and they were analysed separately for the heat accumulation phase and the heat recovery phase. Calculations were performed in a program developed by the author based on the Finite Volume Method (FVM). The main aim is to illustrate the basic features of the developed numerical code and to find effective methods for evaluating the applicability of the modelled structures for heat storage. Except that, in the paper the possibilities are discussed for the use of the source component of the diffusion equation to describe various phenomena of physical, chemical and biological nature. The present article was motivated by the observation that FVM is currently not applied in the process of designing heat storage systems.