Search results for "MODEL"
showing 10 items of 24058 documents
Remarks on regularity for p-Laplacian type equations in non-divergence form
2018
We study a singular or degenerate equation in non-divergence form modeled by the $p$-Laplacian, $$-|Du|^\gamma\left(\Delta u+(p-2)\Delta_\infty^N u\right)=f\ \ \ \ \text{in}\ \ \ \Omega.$$ We investigate local $C^{1,\alpha}$ regularity of viscosity solutions in the full range $\gamma>-1$ and $p>1$, and provide local $W^{2,2}$ estimates in the restricted cases where $p$ is close to 2 and $\gamma$ is close to 0.
Visual Contrast Modulates Operant Learning Responses in Larval Zebrafish.
2018
The larval zebrafish is a promising vertebrate model organism to study neural mechanisms underlying learning and memory due to its small brain and rich behavioral repertoire. Here, we report on a high-throughput operant conditioning system for zebrafish larvae, which can simultaneously train 12 fish to associate a visual conditioned pattern with electroshocks. We find that the learning responses can be enhanced by the visual contrast, not the spatial features of the conditioned patterns, highlighted by several behavioral metrics. By further characterizing the learning curves as well as memory extinction, we demonstrate that the percentage of learners and the memory length increase as the co…
(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…
Study of vocalists' use of emotions in performance preparation
2015
Musicians and educators understand the importance of expressivity in vocal performance. Despite the acceptance of expressivity as a crucial element in musical performance, educators have reported addressing it only cursorily or not addressing it at all when preparing for a performance. For these reasons, this research has focused on techniques used by trained musicians when preparing a performance, to be adapted and applied for use by teachers with their large vocal ensembles. Participants in this study were enrolled in vocal / operatic performance programs at universities in the United States, Ireland, Finland, and Hong Kong. Their progress was tracked throughout the semester by three ques…
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.