Search results for "model."
showing 10 items of 23664 documents
(A,B) In vivo GCaMP6f signals recorded in layers M1, M5 and M9/10 of Mi1 (A) and Tm3 (B) neurons, before (blue, green) and after (gray, red) applicat…
2019
Sensory systems sequentially extract increasingly complex features. ON and OFF pathways, for example, encode increases or decreases of a stimulus from a common input. This ON/OFF pathway split is thought to occur at individual synaptic connections through a sign-inverting synapse in one of the pathways. Here, we show that ON selectivity is a multisynaptic process in the Drosophila visual system. A pharmacogenetics approach demonstrates that both glutamatergic inhibition through GluClα and GABAergic inhibition through Rdl mediate ON responses. Although neurons postsynaptic to the glutamatergic ON pathway input L1 lose all responses in GluClα mutants, they are resistant to a cell-type-specifi…
OCTA atlīdzību apjoma modelēšana, lietojot vispārināto lineāro modeli
2017
Darbs veltīts obligātās civiltiesiskās transportlīdzekļu apdrošināšanas (OCTA) atlīdzību modelēšanai. Modeļu klase, ko izvēlēts lietot, ir vispārinātais lineārais modelis (GLM), kas praksē tiek bieži lietots apdrošināšanas atlīdzību modelēšanai. Darbā aprakstīti vispārinātā lineārā modeļa teorijas pamati un modeļa precizitātes novērtēšanas mēri. Aplūkotas dažādas modeļa parametru novērtēšanas un faktoru atlases metodes, no iegūtajiem modeļiem izvēlēts modelis ar labāko pielāgošanas kvalitāti un precīzāko prognozēšanas spēju. Visbiežāk lietotās metodes - iteratīvā mazāko kvadrātu metode parametru novērtēšanai un soļu regresija faktoru atlasei tika salīdzinātas ar lasso un elastīgo tīklu regu…
Vispārināto lineāro un vispārināto aditīvo modeļu salīdzinājums un pielietojumi
2019
Šajā darbā aprakstītas divas matemātiskās modelēšanas metodes, tās ir, vispārinātais lineārais modelis (generalized linear model (GLM)) un vispārinātais aditīvais modelis (generalized additive model (GAM)), un metodes, ar kurām tie ir saistīti. Darbā ir aprakstītas novērtēšanas metodes un kritēriji, kas tiek izmantoti šādu modeļu analizēšanai un novērtēšanai. Šī darba praktiskā daļa ir veikta programmā R, kur ir salīdzināti vispārinātais lineārais un vispārinātais aditīvais modelis ar mērķi izprast modeļu atšķirības un atšķirt gadījumus, kad labāk izvēlēties vienu vai otru modelēšanas metodi. Veicot darba praktisko daļu, tiek secināts, ka datiem, kuru izkliede nav vienkārša atkarībā no skai…
Vai strukturālās reformas spēs veicināt Latvijas ekonomisko izaugsmi: BMA un GMM novērtējumu liecības
2017
Pētījuma ietvaros tiek pielietota Beijesa modeļu svēršana (BMA) un vispārīgā momentu metode (GMM) Globālās Konkurētspējas apakšindeksu (GCI) datiem, lai identificētu strukturālo reformu jomas, kas var nozīmīgi paātrināt Latvijas ekonomisko izaugsmi. Novērtējumu rezultāti, kuros ņemta vērā gan modeļu nenoteiktība, gan endogenitāte liecina, ka ekonomisko izaugsmi var veicināt ar augstākām investīcijām, zemāku administratīvo slogu, stabilāku makroekonomisko vidi, paaugstinātu ārvalsts tiešo investīciju kvalitāti, kā arī ar attīstītākiem uzņēmējdarbības klasteriem. Ja šajās jomās Latvijas sniegums pēdējo 10 gadu laikā būtu trīs labāko Eiropas Savienības dalībvalstu līmenī, tad ienākumu līmenis …
Impacts of Touch Screen Size, User Interface Design, and Subtask Boundaries on In-Car Task's Visual Demand and Driver Distraction
2020
Visual distraction by secondary in-car tasks is a major contributing factor in traffic incidents. In-car user interface design may mitigate these negative effects but to accomplish this, design factors’ visual distraction potential should be better understood. The effects of touch screen size, user interface design, and subtask boundaries on in-car task's visual demand and visual distraction potential were studied in two driving simulator experiments with 48 participants. Multilevel modeling was utilized to control the visual demands of driving and individual differences on in-car glance durations. The 2.5” larger touch screen slightly decreased the in-car glance durations and had a diminis…
Negative emotional state modulates visual working memory in the late consolidation phase
2020
Although a considerable literature has grown up around the interactions between emotional state and visual working memory (VWM) performance, the mechanism underlying the impact of the negative emotional state on VWM remains unclear. The present study aimed to test whether the influence of emotional state is related to the early phase or late phase of VWM consolidation process. Across three experiments, we found that the negative emotional state did not affect VWM performance when the presentation time of stimuli was short. However, when the presentation time was long, the negative emotional state increased the VWM precision and reduced the VWM number. According to the two-phase model propos…
MODELING OF VOLATILITY IN THE ROMANIAN CAPITAL MARKET
2012
This paper aims to analyze the volatility of capital market in Romania by selecting a portfolio of representative indices (BET BET_FI and RASDAQ_C). In this respect, we want to identify the most appropriate model to estimate volatility by using modern econometric tools and useful GARCH models respectively. The study results highlight that EGARCH(1,1) model has managed to eliminate all traces of statistically significant autocorrelation and ARCH effects from the residuals from daily series, giving an accurate image of the Romanian capital market volatility.
Ultraviolet imaging of volcanic plumes: A new paradigm in volcanology
2017
Ultraviolet imaging has been applied in volcanology over the last ten years or so. This provides considerably higher temporal and spatial resolution volcanic gas emission rate data than available previously, enabling the volcanology community to investigate a range of far faster plume degassing processes than achievable hitherto. To date, this has covered rapid oscillations in passive degassing through conduits and lava lakes, as well as puffing and explosions, facilitating exciting connections to be made for the first time between previously rather separate sub-disciplines of volcanology. Firstly, there has been corroboration between geophysical and degassing datasets at â1 Hz, expeditin…
Decoupled control scheme of grid-connected split-source inverters
2017
Grid-connected power conversion systems for renewable energy sources must fulfill several requirements, e.g., the high efficiency, the reduced cost and complexity, and, quite often, the boost capabilities that is usually achieved using a front-end dc–dc boost converter before the inversion stage, leading to a two-stage architecture. Meanwhile, single-stage power conversion systems, which perform the boosting operation within the inversion one, offer some potential advantages, in terms of reducing the complexity and the volume of the whole system. Among several proposed options, the split-source inverter (SSI) has been recently proposed by Abdelhakim et al. as an alternative option with some…
Modellazione numerica del comportamento meccanico delle volte catalane
2010
Il presente lavoro riguarda la modellazione numerica del comportamento costitutivo delle cosiddette volte in foglio (le bóvedas tabicadas) che rappresentano una delle tecniche edilizie tradizionali catalane più diffusamente impiegate da alcuni tra i più grandi architetti spagnoli (primo fra tutti Gaudí) alla fine del XIX secolo [1-3]. Tali volte risultano fondamentalmente costituite da strati alternati di spessore in generale pressoché uguale di mattoni e di malta. Questa particolare caratteristica viene studiata in questo lavoro nel quale si vuole confrontare la modellazione del comportamento costitutivo considerando il materiale come ideale omogeneo con quella ottenuta modellando il mater…