Analysis and Design of Electronic Commerce

V mojej bakalárskej práci som analyzoval prostredie trhu, v ktorom sa nachádzajú konkurenčné internetové obchody. Následne som spracoval návrh a riešenie internetového obchodu zameraného na predaj tovarov a služieb s prioritou maximálne možne uspokojiť zákazníka. Predkladaná bakalárska práca obsahuje teoretické východiská k vymedzenej problematike a je určitým nástrojom na návrh a riešenie internetového obchodu, ale aj jeho adaptáciu do konkurenčného prostredia trhu.In this bachelor’s thesis I analyzed market environment where competitive internet shops are located. In next step I processed proposal and solution of e-shop focused on selling goods and services giving maximum priority to satisfy the customer. This work provides the theoretical basis for defined problems and is kind of solution of e-shop and also is a tool for it's adaptation to competitive environment.

Design of gas flow model

katedra: KMO; přílohy: 1 cd; rozsah: 55 s.Tato práce se zabývá implementací a numerickým řešením úlohy vazkého izotermického proudění stlačitelné tekutiny pomocí metody konečných diferencí (FDM - Finite Difference Method) a metody konečných objemů (FVM - Finite Volume Method). Pro metodu konečných diferencí je navrženo explicitní a implicitní schéma a pro metodu konečných objemů je to explicitní Lax-Friedrichsovo schéma. Pro matematický popis proudění jsou použity Navier-Stokesova rovnice, která popisuje zákon zachování hybnosti vazké tekutiny, rovnice kontinuity, která vyjadřuje zákon zachování hmoty, a stavová rovnice plynu. Všechna schémata se porovnávají na navržených testovacích úlohách, na dvojdimenzionální obdélníkové oblasti bez překážek a jednou vstupní hranou, jednou výstupní hranou a dvěma nepropustnými hranami. V práci se porovnává vliv velikosti časového kroku, prostorového kroku a dynamické viskozity na stabilitu jednotlivých schémat.The topic of this work is numerical solution and implementation of isothermal viscous compressible flow using the Finite Difference Method and Finite Volume Method. There are different schemes proposed for both methods - implicit and explicit scheme for the Finite Difference Method and the Lax-Friedrichs explicit scheme for the Finite Volume Method. There is a mathematical description of the flow, which is based on the following three equations: Navier-Stokes equation which represents the momentum conservation law, continuity equation which represents the mass conservation law and the gas state equation. All of those schemes are compared on testing problems. The flow is solved in a two-dimensional rectangular space without barriers. There are one inlet side and one outlet side in the area. Two other sides are impermeable. In this work, the effect of size of time and spatial discretization step and size of dynamic viscosity parameter on results of individual schemes is compared

Zig-zag charged domain walls in ferroelectric PbTiO3_3

We report a theoretical investigation of a charged 180$^\circ$ domain wall in ferroelectric PbTiO$_3$, compensated by randomly distributed immobile charge defects. For this we utilize atomistic shell-model simulations and continuous phase-field simulations in the framework of the Ginzburg-Landau-Devonshire model. We predict that domain walls form a zig-zag pattern and we discuss its properties in a broad interval of compensation-region widths, ranging from a couple to over a hundred nanometers

A Novel Statistical Model for Predicting the Efficacy of Vagal Nerve Stimulation in Patients With Epilepsy (Pre-X-Stim) Is Applicable to Different EEG Systems

Background: Identifying patients with intractable epilepsy who would benefit from therapeutic chronic vagal nerve stimulation (VNS) preoperatively remains a major clinical challenge. We have developed a statistical model for predicting VNS efficacy using only routine preimplantation electroencephalogram (EEG) recorded with the TruScan EEG device (Brazdil et al., 2019). It remains to be seen, however, if this model can be applied in different clinical settings. Objective: To validate our model using EEG data acquired with a different recording system. Methods: We identified a validation cohort of eight patients implanted with VNS, whose preimplantation EEG was recorded on the BrainScope device and who underwent the EEG recording according to the protocol. The classifier developed in our earlier work, named Pre-X-Stim, was then employed to classify these patients as predicted responders or non-responders based on the dynamics in EEG power spectra. Predicted and real-world outcomes were compared to establish the applicability of this classifier. In total, two validation experiments were performed using two different validation approaches (single classifier or classifier voting). Results: The classifier achieved 75% accuracy, 67% sensitivity, and 100% specificity. Only two patients, both real-life responders, were classified incorrectly in both validation experiments. Conclusion: We have validated the Pre-X-Stim model on EEGs from a different recording system, which indicates its application under different technical conditions. Our approach, based on preoperative EEG, is easily applied and financially undemanding and presents great potential for real-world clinical use

On the Time Course of Synchronization Patterns of Neuronal Discharges in the Human Brain during Cognitive Tasks

Using intracerebral EEG recordings in a large cohort of human subjects, we investigate the time course of neural cross-talk during a simple cognitive task. Our results show that human brain dynamics undergo a characteristic sequence of synchronization patterns across different frequency bands following a visual oddball stimulus. In particular, an initial global reorganization in the delta and theta bands (2–8 Hz) is followed by gamma (20–95 Hz) and then beta band (12–20 Hz) synchrony

Left Ventricular Myocardial Septal Pacing in Close Proximity to LBB Does Not Prolong the Duration of the Left Ventricular Lateral Wall Depolarization Compared to LBB Pacing

Background: Three different ventricular capture types are observed during left bundle branch pacing (LBBp). They are selective LBB pacing (sLBBp), non-selective LBB pacing (nsLBBp), and myocardial left septal pacing transiting from nsLBBp while decreasing the pacing output (LVSP). Study aimed to compare differences in ventricular depolarization between these captures using ultra-high-frequency electrocardiography (UHF-ECG). Methods: Using decremental pacing voltage output, we identified and studied nsLBBp, sLBBp, and LVSP in patients with bradycardia. Timing of ventricular activations in precordial leads was displayed using UHF-ECGs, and electrical dyssynchrony (e-DYS) was calculated as the difference between the first and last activation. The durations of local depolarizations (Vd) were determined as the width of the UHF-QRS complex at 50% of its amplitude. Results: In 57 consecutive patients, data were collected during nsLBBp (n = 57), LVSP (n = 34), and sLBBp (n = 23). Interventricular dyssynchrony (e-DYS) was significantly lower during LVSP 16 ms (21; 11), than nsLBBp 24 ms (28; 20) and sLBBp 31 ms (36; 25). LVSP had the same V1d-V8d as nsLBBp and sLBBp except for V3d, which during LVSP was shorter than sLBBp; the mean difference 9 ms (16; 1), p = 0.01. LVSP caused less interventricular dyssynchrony and the same or better local depolarization durations than nsLBBp and sLBBp irrespective of QRS morphology during spontaneous rhythm or paced QRS axis. Conclusions: In patients with bradycardia, LVSP in close proximity to LBB resulted in better interventricular synchrony than nsLBBp and sLBBp and did not significantly prolong depolarization of the left ventricular lateral wall