UHF-sagedusala sidesüsteem kuupsatelliidile

Communication is one of the most important parts of any satellite. Estonian future satellite ESTCube-2 needs a new and advanced communication system to upload commands and firmware and download telemetry and images. The goal of this masters thesis was to determine system architecture and develop first electrical prototype of this communication system. Strengths and weaknesses of previous systems was researched and new system design was determined. Necessary single components were determined. Single components were built to prototypes, tested and characterised. RF parameters of filters were measured and found to be suitable for the system. Components were integrated to a first electrical model of the communication system. All of the work meets the requirements set to the system. Since power is very limited on small satellites focus was making the communication system energy efficient. This work could not be done without support from people in ESTCube team. Most of the necessary knowledge was taught by supervisors. Much of supporting work was done by other members of communication subsystem team – Ahti Laurisson, Taavi Adamson and Laur Joost. Work on the system continues in to develop full software and test all the component integration. This work contains technical drawings and description of developed system. It also provides information for developing other similar systems

Trusting our own minds

When it comes to the metaethical task of explaining and making sense of what it is that we are doing while doing ethics, the subject of moral objectivity occupies an important and special place within that task. Thus, it is often agreed that being able to explain and justify the objective features of common moral practice is one of if not the most important task for any metaethical theory to undertake. In this dissertation, I tackle the issue of ethical objectivity on behalf of metaethical constructivism. To be more precise, my aim is to make plausible, strengthen, and defend the constructivist original contribution to contemporary metaethics by developing a novel constructivist account on the objectivity of ethics. While the account that I develop herein presents a novel and independent approach to the subject of moral objectivity on behalf of constructivism, it also places itself between the two other positions within the constructivist camp that openly strive to secure ethical objectivity – namely Kantianism on the one hand, and the more recently developed Humean objectivist view on the other. It is for the latter reason that I call my own view the hybrid view

COGNITIVE AND MOTOR PROCESSES IN A VOLLEYBALL SPECIFIC ANTICIPATION TASK

The purpose of the study was to investigate the relationship between cognitive and motor processes in a volleyball specific anticipation task with temporal video occlusion. Ten middle blockers of the national 2nd-4th division volleyball league were supposed to anticipate the setting direction presented on a screen, which occluded at three different occlusion times and respond with either a specific blocking movement (motor response) or key press (cognitive response). The participants showed only small significant differences in the kinematics of the block movement between the examined occlusion conditions. The participants showed a variable time of movement initiation with a shorter total duration with later occlusion although the movement time was shorter. The results illustrate a close temporal adaptation of the block movement to the presented setting situation

COMPARISON OF CLASSICAL AND INTERACTIVE MULTI-ROBOT EXPLORATION STRATEGIES IN POPULATED ENVIRONMENTS

Multi-robot exploration consists in coordinating robots for mapping an unknown environment. It raises several issues concerning task allocation, robot control, path planning and communication. We study exploration in populated environments, in which pedestrian flows can severely impact performances. However, humans have adaptive skills for taking advantage of these flows while moving. Therefore, in order to exploit these human abilities, we propose a novel exploration strategy that explicitly allows for human-robot interactions. Our model for exploration in populated environments combines the classical frontier-based strategy with our interactive approach. We implement interactions where robots can locally choose a human guide to follow and define a parametric heuristic to balance interaction and frontier assignments. Finally, we evaluate to which extent human presence impacts our exploration model in terms of coverage ratio, travelled distance and elapsed time to completion

COMPARISON OF CLASSICAL AND INTERACTIVE MULTI-ROBOT EXPLORATION STRATEGIES IN POPULATED ENVIRONMENTS

Multi-robot exploration consists in coordinating robots for mapping an unknown environment. It raises several issues concerning task allocation, robot control, path planning and communication. We study exploration in populated environments, in which pedestrian flows can severely impact performances. However, humans have adaptive skills for taking advantage of these flows while moving. Therefore, in order to exploit these human abilities, we propose a novel exploration strategy that explicitly allows for human-robot interactions. Our model for exploration in populated environments combines the classical frontier-based strategy with our interactive approach. We implement interactions where robots can locally choose a human guide to follow and define a parametric heuristic to balance interaction and frontier assignments. Finally, we evaluate to which extent human presence impacts our exploration model in terms of coverage ratio, travelled distance and elapsed time to completion

Piesoelektrilise mootori juhtseade kuupsatelliidile

http://tartu.ester.ee/record=b2655797~S1*es

Perfektsionismi struktuuri areng varases puberteedieas lastel

http://tartu.ester.ee/record=b2656582~S1*es

Wetting-Induced Polyelectrolyte Pore Bridging

Active layers of ion separation membranes often consist of charged layers that retain ions based on electrostatic repulsion. Conventional fabrication of these layers, such as polyelectrolyte deposition, can in some cases lead to excess coating to prevent defects in the active layer. This excess deposition increases the overall membrane transport resistance. The study at hand presents a manufacturing procedure for controlled polyelectrolyte complexation in and on porous supports by support wetting control. Pre-wetting of the microfiltration membrane support, or even supports with larger pore sizes, leads to ternary phase boundaries of the support, the coating solution, and the pre-wetting agent. At these phase boundaries, polyelectrolytes can be complexated to form partially freestanding selective structures bridging the pores. This polyelectrolyte complex formation control allows the production of membranes with evenly distributed polyelectrolyte layers, providing (1) fewer coating steps needed for defect-free active layers, (2) larger support diameters that can be bridged, and (3) a precise position control of the formed polyelectrolyte multilayers. We further analyze the formed structures regarding their position, composition, and diffusion dialysis performance