Search results for "Markov"
showing 10 items of 628 documents
Akciju tirgus cenu prognozēšana, izmantojot slēptos Markova modeļus
2017
Bakalaura darba pētāmā problēma ir slēpto Markova modeļu pielietojums akciju tirgus cenu prognozēšanai. Darbs ir veltīts slēpto Markova modeļu un to galveno pamatproblēmu izpētei un risināšanai, kā arī akciju tirgus cenu prognozēšanai trīs uzņēmumu akcijām, izmantojot gan slēptos Markova modeļus ar diviem slēptajiem stāvokļiem, gan ar trīs slēptajiem stāvokļiem. Katra uzņēmuma prognožu precizitātes ir salīdzinātas, izmantojot vidējo absolūto procentuālo kļūdu un izveidojot grafisku attēlojumu, salīdzinot reālās akciju cenas ar iegūtajām prognozētajām akciju cenām. Datu analizēšanai un aprēķiniem izmantota programma Microsoft Excel, kā arī statistisko aprēķinu programma R.
Alueellisen työttömyyden pysyvyys Suomessa
2010
Tässä tutkimuksessa selvitettiin alueellisen työttömyyden ja työttömyyserojen ajallista kehitystä, rakennetta ja pysyvyyttä sekä alueellisten työmarkkinoiden toimivuutta. Myös syitä pysyvyyden esiintymiselle tutkittiin. Tarkasteltavia alueyksiköitä olivat seutukunnat. Työttömyyden ajallista kehitystä, rakennetta ja pysyvyyttä tutkittiin keskihajonnan, variaatiokertoimen, niin kutsuttujen Markovin siirtymämatriisien ja autoregressiivisten mallien avulla. Pysyvyyden syitä etsittiin mallinnuksen avulla. Analyysin pohjana toimi kaksi erillistä Tilastokeskuksen ja Terveyden ja hyvinvoinnin laitoksen aineistoista muodostettua paneeliaineistoa. Mallinnuksen aineisto oli vuosilta 1998–2007. Muut an…
Cluster priors in the Bayesian modelling of fMRI data
2001
All-sky search in early O3 LIGO data for continuous gravitational-wave signals from unknown neutron stars in binary systems
2021
Rapidly spinning neutron stars are promising sources of continuous gravitational waves. Detecting such a signal would allow probing of the physical properties of matter under extreme conditions. A significant fraction of the known pulsar population belongs to binary systems. Searching for unknown neutron stars in binary systems requires specialized algorithms to address unknown orbital frequency modulations. We present a search for continuous gravitational waves emitted by neutron stars in binary systems in early data from the third observing run of the Advanced LIGO and Advanced Virgo detectors using the semicoherent, GPU-accelerated, binaryskyhough pipeline. The search analyzes the most s…
Exploiting Semantic Trajectories Using HMMs and BIM for Worker Safety in Dynamic Environments
2020
International audience; Understanding dynamic behaviors of moving objects using positioning technologies for construction safety monitoring is still an open research issue. One task; that is a small subset in the widespread field of objects dynamics is the enrichment of the location data of users with the semantic information for studying their mobility patterns in the context of the environment. However, incorporating the semantics related to the environment gets complex in case of the dynamic construction sites where the site spaces are kept evolving with time. For instance, new walls and infrastructure supports are added often on sites, while others are detached. Similar situations open …
Analysis on channel bonding/aggregation for multi-channel cognitive radio networks
2010
Channel bonding/aggregation techniques, which assemble several channels together as one channel, could be used in cognitive radio networks for the purpose of achieving better bandwidth utilization. In existing work on this topic, channel bonding/aggregation is focused on the cases when primary channels are time slotted or stationary as compared with secondary users' activities. In this paper, we analyze the performance of channel bonding/aggregation strategies when primary channels are not time slotted and the time scale of primary activities is at the same level as the secondary users', given that spectrum handover is not allowed. Continuous time Markov chain models are built in order to a…
Priority Enabled Grant-Free Access With Dynamic Slot Allocation for Heterogeneous mMTC Traffic in 5G NR Networks
2021
Although grant-based mechanisms have been a predominant approach for wireless access for years, the additional latency required for initial handshake message exchange and the extra control overhead for packet transmissions have stimulated the emergence of grant-free (GF) transmission. GF access provides a promising mechanism for carrying low and moderate traffic with small data and fits especially well for massive machine type communications (mMTC) applications. Despite a surge of interest in GF access, how to handle heterogeneous mMTC traffic based on GF mechanisms has not been investigated in depth. In this paper, we propose a priority enabled GF access scheme which performs dynamic slot …
An adaptive probabilistic approach to goal-level imitation learning
2010
Imitation learning has been recognized as a promising technique to teach robots advanced skills. It is based on the idea that robots could learn new behaviors by observing and imitating the behaviors of other skilled actors. We propose an adaptive probabilistic graphical model which copes with three core issues of any imitative behavior: observation, representation and reproduction of skills. Our model, Growing Hierarchical Dynamic Bayesian Network (GHDBN), is hierarchical (i.e. able to characterize structured behaviors at different levels of abstraction), and growing (i.e. skills are learned or updated incrementally - and at each level of abstraction - every time a new observation sequence…
An adaptive probabilistic graphical model for representing skills in PbD settings
2010
Learning from Errors: Detecting ZigBee Interference in WiFi Networks
2014
In this work we show how to detect ZigBee interference on commodity WiFi cards by monitoring the reception errors, such as synchronization errors, invalid header formats, too long frames, etc., caused by ZigBee transmissions. Indeed, in presence of non-WiFi modulated signals, the occurrence of these types of errors follows statistics that can be easily recognized. Moreover, the duration of the error bursts depends on the transmission interval of the interference source, while the error spacing depends on the receiver implementation. On the basis of these considerations, we propose the adoption of hidden Markov chains for characterizing the behavior of WiFi receivers in presence of controlle…