A note on the motion of an ocean bacterium in a linear shear flow

This paper treats a simple model, which can be exactly solved, motivated by the back-and-forth motion of ocean bacteria. In particular, the probability is determined that a bacterium moving randomly along a fluid line through the origin in a linear shear flow hits the origin before time

On Taylor dispersion in oscillatory channel flows

We revisit Taylor dispersion in oscillatory flows at zero Reynolds number, giving an alternative method of calculating the Taylor dispersivity that is easier to use with computer algebra packages to obtain exact expressions. We consider the effect of out-of-phase oscillatory shear and Poiseuille flow, and show that the resulting Taylor dispersivity is independent of the phase difference. We also determine exact expressions for several examples of oscillatory power-law fluid flows

Numerically optimized Markovian coupling and mixing in one-dimensional maps

Algorithms are introduced that produce optimal Markovian couplings for large finite-state-space discrete-time Markov chains with sparse transition matrices; these algorithms are applied to some toy models motivated by fluid-dynamical mixing problems at high Peclét number. An alternative definition of the time-scale of a mixing process is suggested. Finally, these algorithms are applied to the problem of coupling diffusion processes in an acute-angled triangle, and some of the simplifications that occur in continuum coupling problems are discussed

MIS 475 Commerce on the Internet

Course syllabus for MIS 475 Commerce on the Internet Course description: The purpose of this course is to provide students with a balanced coverage of the business and technology elements of e-business and e-commerce, together referred to as electronic commerce. The course explains the basic concepts of business uses for the World Wide Web and uses a variety of software tools for effective Web development as it pertains to the business world. The course also gives an overview of international, legal, ethical and tax issues that can arise in the conduct of electronic commerce

Leader-follower System for Unmanned Ground Vehicle

Mehitamata sõidukeid saab kasutada efektiivselt, kui neil on autonoomse sõitmise võimekus.Autonoomse sõitmise üks funktsionaalsustest on juht-järgijasüsteem, mis tähendab, et robot peab järgi minema etteantud objektile. Tavaliselt on defineeritud objektiks inimene, mis võimaldab hoida inimeste käed vabana, võrreldes situatsiooniga, kus masina liigutamiseks tuleb kasutada pulti, mis muudab sõdurid militaarolukorras haavatavaks sihtmärgiks. Olemasolevad juht-järgija süsteemid kasutavad funktsioneerimiseks kombinatsiooni erinevatest sensoritest, kasutades nii LIDAReid, GPS-i, infrapunamarkereid kui ka kaameraid. Selle töö eesmärgiks on arendada ja testida juht-järgijasüsteem, mis kasutab ainult kaamerasisendit ning mis oma kontseptsioonilt peaks olema võimeline järgnema igale objektile, st objekti tüüp ja välimus ei pea olema eeldefineeritud.Täpsemalt kasutab süsteem käitumuslikku kloonimist sügavate konvolutsiooniliste tehisnärvivõrkude treenimiseks, et ennustada kaamera sisendi põhjal roboti liigutamiseks vajalikke kiiruse ja pööramise käske. Tulemused näitavad, et pakutud süsteem töötab, kuid vajab edasiarendust, et teha see reaalse olukorra jaoks piisavalt robustseks ning turvaliseks.Unmanned ground vehicles can be utilized effectively, if they have autonomous capabilities. One of those capabilities is leader-follower functionality, which means that the robot has to follow a predefined object. Usually the predefined object is a person, which is still more effective than controlling the robot with teleoperation using a remote control. It is worthwhile, because teleoperation requires the full attention of the operator while leader-follower system allows the person to keep their situational awareness, which is essential in a military environment. Leader-follower systems often exploit multipletechnologies: LIDARs, GPS, infrared markers, radar transponder tags and cameras. The aim of this thesis is to develop and test the proof of concept leader-follower system, which relies on camera vision only and is able to follow any object which means that the class of the object does not have to be predefined. Specifically, the approach uses behavioral cloning to train deep siamese network with convolutional layers to determine the velocity and turning commands of the vehicle based on input from camera. The results show that the proof of concept system works, but requires further development in order to make it robust and safe

Characterization of natural sedimentary dolomite and limestone reference materials from Geological Survey of Estonia using LA-ICP-MS

Sedimentary dolomite (Es-16, Es-18) and limestone (Es-3, Es-14, Es-17) from Geological Survey of Estonia have been used as reference materials in X-ray fluorescence analysis in Estonian laboratories. Homogeneity of these materials was investigated with laser-ablation inductively coupled plasma mass-spectrometry using MACS-3 and NIST612 certified reference materials for calibration. Natural limestone CAL-S from CRPG was analyzed for overall comparison. Potential application of Es’s as micro-analytical reference materials was evaluated by quantification of uncertainty due to inhomogeneity and estimation of homogeneity index. Es-17 and Es-16 were found most homogenous. More homogenous distribution and higher concentrations of Cs and Rb were found in Es-17, Es-3 and Es-16 than in MACS-3. Inhomogenous distribution of rare earth elements was observed in Es-14, Es-18 and Es-17