1. Dealing with network changes in cellular fingerprint positioning systemsChris Marshall, Federico Pittino, Andrea Dalla Torre, Donatella Gubiani, Angelo Montanari, Paolo Gallo, Andrea Viel, 2017, objavljeni znanstveni prispevek na konferenci Opis: Besides being a fundamental infrastructure for communication, cellular networks are exploited for positioning through signal fingerprinting. Maintaining the fingerprint database consistent and up-to-date is a challenging task in many fingerprint positioning systems, e.g., in those populated by a crowd-sourcing effort. To this end, detecting and tracking the changes in the configurations of cellular networks over time is recognized as a relevant problem. In this paper, we show that to cope with this problem we can successfully exploit information provided by Timing Advance (TA). As a by-product, we prove that TA can improve the fingerprint candidate selection phase, reducing the number of fingerprints to provide as input to positioning algorithms. The effectiveness of the proposed improvements has been tested on a fingerprint positioning system with a large fingerprint dataset collected over a period of 2 years.
Najdeno v: ključnih besedah
Ključne besede: fingerprint positioning systems, cellular communication networks, network changes
Objavljeno: 13.06.2018; Ogledov: 3257; Prenosov: 0
 Polno besedilo (4,64 MB) |
2. A Network of ThemesNarvika Bovcon, Aleš Vaupotič, 2017, izvirni znanstveni članek Opis: Gerhard Richter's books Text – a collection of painter's verbal statements about his artistic method – and Atlas – 783 sheets with images, mainly photographs and visual notations – are two archives that complement the understanding of his diverse artistic practice. The paper presents a textual model that experimentally simulates a possible ordering principle for archives. Richter's statements in the book Text are cut up and used as short quotations. Those that relate to multiple aspects of the painter's oeuvre are identified as hubs in the semantic network. The hubs are organized paratactically, as an array of different themes. The paper presents a methodological hypothesis and an experimental model that aim to connect the research of real networks with the paradigms of humanistic interpretation. We have to bear in mind that the network is a result of the researcher's interpretative approach, which is added to the initial archive included in the book Text. The breaking up of Richter's poetics into atoms of quotations is an experimental proposal of a new textuality in art history and humanities, which has its own history. In comparison to digital archives with complex interfaces that often tend to obscure the content, the elements in our experiment appear as specific configurations of the semantic network and are presented in a limited number of linear texts. The method of listing of quotations gathers the fragments into a potential “whole”, i.e. a narrativized gateway to an archive according to the researcher's interpretation.
Najdeno v: ključnih besedah
Ključne besede: artistic archive, narrativization, networks, author's poetics, Gerhard Richter
Objavljeno: 11.07.2017; Ogledov: 3151; Prenosov: 233
Polno besedilo (400,90 KB) |
3. Weak forms of shadowing in topological dynamicsSergey Kryzhevich, Danila Cherkashin, 2017, izvirni znanstveni članek Opis: We consider continuous maps of compact metric spaces. It is proved that every pseudotrajectory with sufficiently small errors contains a subsequence of positive density that is point-wise close to a subsequence of an exact trajectory with the same indices. Also, we study homeomorphisms such that any pseudotrajectory can be shadowed by a finite number of exact orbits. In terms of numerical methods this property (we call it multishadowing) implies possibility to calculate minimal points of the dynamical system.
We prove that for the non-wandering case multishadowing is equivalent to density of minimal points. Moreover, it is equivalent to existence of a family of $\varepsilon$-networks ($\varepsilon > 0$) whose iterations are also $\varepsilon$-networks. Relations between multishadowing and some ergodic and topological properties of dynamical systems are discussed.
Najdeno v: ključnih besedah
Ključne besede: Topological dynamics, minimal points, invariant measure, shadowing, chain recurrence, $\varepsilon$-networks, syndetic sets
Objavljeno: 27.07.2017; Ogledov: 3607; Prenosov: 0
Polno besedilo (499,38 KB) |
4. Comparative analysis of epidemiological models for COVID-19 pandemic predictionsSaibal K. Pal, Rajan Gupta, Gaurav Pandey, 2021, izvirni znanstveni članek Opis: Epidemiological modeling is an important problem around the world. This research presents COVID-19 analysis to understand which model works better for different regions. A comparative analysis of three growth curve fitting models (Gompertz, Logistic, and Exponential), two mathematical models (SEIR and IDEA), two forecasting models (Holt’s exponential and ARIMA), and four machine/deep learning models (Neural Network, LSTM Networks, GANs, and Random Forest) using three evaluation criteria on ten prominent regions around the world from North America, South America, Europe, and Asia has been presented. The minimum and median values for RMSE were 1.8 and 5372.9; the values for the mean absolute percentage error were 0.005
and 6.63; and the values for AIC were 87.07 and 613.3, respectively, from a total of 125 experiments across 10 regions. The growth curve fitting models worked well where flattening of the cases has started. Based on region’s growth curve, a relevant model from the list can be used for predicting the number of infected cases for COVID-19. Some other models used in forecasting the number of cases have been added in the future work section, which can help researchers to forecast the number of cases in different regions of the world.
Najdeno v: ključnih besedah
Ključne besede: epidemic modeling, machine learning, neural networks, pandemic forecasting, time-series forecasting
Objavljeno: 15.07.2021; Ogledov: 1458; Prenosov: 31
Polno besedilo (3,16 MB)
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8. Multiple allocation p-hub location problem for content placement in VoD services: a differential evolution based approachGoutam Sen, Soumen Atta, 2020, izvirni znanstveni članek Opis: In video-on-demand (VoD) services, large volumes of digital data are kept at hubs which are spatially distributed over large geographic areas and users are connected to these hubs based on their demands. In this article, we consider a large database of video files, that are pre-partitioned to multiple segments based on the demand patterns of users. These segments are restricted to be located only in hubs. Here, users are allowed to be allocated to multiple hubs and all hubs are assumed to be connected with each other. We jointly decide the location of hubs, the placement of segments to these hubs and then the assignment of users to these hubs as per their demand patterns and finally, we find the optimal paths to route the demands of users for different segments having the objective of minimizing the total routing cost. In this article, a differential evolution (DE) based method is proposed to solve the problem. The proposed DE-based method utilizes an efficient function to evaluate the objective value of a candidate solution to the proposed problem. It also incorporates two problem-specific solution refinement techniques for faster convergence. Instances of the problem are generated from the real world movie database and the proposed method is applied to these instances and the performance is evaluated against the benchmark results obtained from CPLEX.
Najdeno v: ključnih besedah
Ključne besede: Video-on-demand (VoD) services, Content distribution networks, Database segment location, Hub location, Multiple hub allocation, Differential evolution (DE), IBM ILOG CPLEX
Objavljeno: 17.04.2023; Ogledov: 133; Prenosov: 0
Polno besedilo (2,15 MB) |
