No. 8/2018

Online archive of Computer Science and Mathematical Modelling

No. 8/2018

  1. F. Darnowski, A. Chojnacki - Writing and Deleting files on hard drives with NTFS
    Pages: 5 - 15
    Abstract: The goal of this article was to present detailed information about writing and deleting process on the NTFS (New Technology File System) formatted drives. The most important are the algorithms used by computer to write data BFA (Best Fit Algorithm) and FFA (First-Free Algorithm) to update $MFT (Master File Table). The naming convention of the areas of the drive is presented. The proposed rules of writing and deleting algorithm were successfully validated with real NTFS volume.
    Keywords hard disk, NTFS, $MFT.
    Full article: PDF icon 5_15_new_ach_fd_csmm_8_p.pdf
  2. M. Jankowski - Ensemble Methods for Improving Classification of Data Produced by Latent Dirichlet Allocation
    Pages: 17 - 28
    Abstract: Topic models are very popular methods of text analysis. The most popular algorithm for topic modelling is LDA (Latent Dirichlet Allocation). Recently, many new methods were proposed, that enable the usage of this model in large scale processing. One of the problem is, that a data scientist has to choose the number of topics manually. This step requires some previous analysis. A few methods were proposed to automatize this step, but none of them works very well if LDA is used as a preprocessing for further classification. In this paper, we propose an ensemble approach which allows us to use more than one model at prediction phase, at the same time, reducing the need of finding a single best number of topics. We have also analyzed a few methods of estimating topic number.
    Keywords Dimensionality reduction, classification, machine learning, natural language processing, topic modelling.
    Full article: PDF icon 17_28_mjankowski_ensemble_csmm_8_2018_p.pdf
  3. D. Pierzchała, P. Czuba - Method of agents’ state estimation in multiresolution multiagent simulation
    Pages: 29 - 39
    Abstract: The paper proposes the multiagent techniques for approximation of agent’s state in the multiresolution multiagent simulation. The key methods we have used for state aggregation and disaggregation are: consensus algorithm and formation control. The idea of the coordination of multiple agents has emerged from both observation and simulation of a collective behavior of biological entities. The consensus algorithms are commonly used for the cooperative control problems in the multiagent systems, whilst the formation control is the most popular and fundamental motion coordination problem in the multiagent systems, where agents converge to predefined geometric shapes. The presented approach shows that multiagent methods seem to be very promising in multiresolution simulation. Consensus and formation control algorithms remove necessity to specify the much more complex algorithms for the aggregation and disaggregation needs.
    Keywords multiresolution multiagent simulation, multiagent systems, multiagent networks, formation control.
    Full article: PDF icon 29_39_method_of_agents_csmm_8_p.pdf
  4. P.A. Ryszawa - On some specific cases of quantum state in testing its separability
    Pages: 41 - 46
    Abstract: This paper shows a simple computational scheme for determining whether a particular quantum state in a specific form is separable across two given sets of qubits. That is, given a set of qubits partitioned into two, it answers the question: does the original state have a separable form as a tensor product of some two other states, which are set up of the two given subsets of qubits?
    Keywords quantum computing, quantum register, quantum entanglement, quantum separability.
    Full article: PDF icon 41_46_paryszawa_qseparable_csmm_8_2018_p.pdf
  5. K. Sosnowski - The use of electroencephalography as a future-oriented brain-computer interface. Current concepts, solutions, technologies that allow communication through thoughts
    Pages: 47 - 52
    Abstract: Nowadays, brain-computer interfaces are gaining more and more popularity. Research centers develop new methods of human communication with devices through thoughts. There are many methods used for this kind of interfaces, however, the most widespread is electroencephalography (EEG). There are many reasons for this fact, it is a method that is relatively cheap compared to other methods. Less complex technical tools and apparatus are required to operate it. Another advantage of this method, unlike others, is its non-invasiveness. Unfortunately, current brain-computer interfaces do not offer high data rates. However, time plays a smaller role when we are dealing with a disabled person who regains the ability to communicate with the world through the interface controlled by thoughts. This paper is the beginning of a series of papers in which the author will describe in detail the elements of brain-computer interfaces, as well as improvements that can be applied to them to improve their properties.
    Keywords Brain-computer interface, BCI, Electroencephalography, EEG.
    Full article: PDF icon 47_52_theuseofelectro_csmm_8_2018_p.pdf