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<p> Cooperative teleoperation combines two traditional areas of robotics, i.e. teleoperation and collaborative manipulation. Cooperative telerobotic systems consist of multiple pairs of master I slave robotic manipulators operating in a shared environment. Due to dynamic interaction among slave manipulators as well as communication latency, control of such systems is particularly challenging and the application of standard teleoperation controller may result in instability. </p> <p> In this thesis a multilateral control framework is proposed for cooperative teleoperation systems that allows for transmission of position and force information between all master and slave robots rather than merely between corresponding units. Two different control approaches are introduced that establish kinematic correspondence among masters and slaves. The operators are presented with a virtual intervening tool in order to collaboratively interact with the environment. Models of operators, master and slave robots, tool, and environment are incorporated in the design. </p> <p> A multilateral adaptive nonlinear control architecture is proposed. Performance and stability of cooperative teleoperation systems are addressed under dynamic interactions between slave robots in the presence of model uncertainty. The robustness of the controller with respect to communication latency is also analyzed. Simulation and experimental studies demonstrate that the proposed approach is highly effective in all phases of a teleoperation task, i.e. in free motion and in contact with both flexible and rigid environments. </p> <p> The second approach involves finite-dimensional state-space models that incorporate the delay for free motion/ soft contact as well as rigid contact modes of operation. Local dynamic linearization control laws are employed to linearize robotic manipulators' dynamics. Model-based discrete-time Linear Quadratic Gaussian (LQG) controllers are proposed that can deliver a stable transparent response for each phase of operation. The robustness of these controllers with respect to parameter uncertainty is examined via the Nyquist analysis. Simulation results demonstrate the effectiveness of the proposed approach. </p> / Thesis / Master of Applied Science (MASc)

<p> Cooperative teleoperation combines two traditional areas of robotics, i.e. teleoperation and collaborative manipulation. Cooperative telerobotic systems consist of multiple pairs of master I slave robotic manipulators operating in a shared environment. Due to dynamic interaction among slave manipulators as well as communication latency, control of such systems is particularly challenging and the application of standard teleoperation controller may result in instability. </p> <p> In this thesis a multilateral control framework is proposed for cooperative teleoperation systems that allows for transmission of position and force information between all master and slave robots rather than merely between corresponding units. Two different control approaches are introduced that establish kinematic correspondence among masters and slaves. The operators are presented with a virtual intervening tool in order to collaboratively interact with the environment. Models of operators, master and slave robots, tool, and environment are incorporated in the design. </p> <p> A multilateral adaptive nonlinear control architecture is proposed. Performance and stability of cooperative teleoperation systems are addressed under dynamic interactions between slave robots in the presence of model uncertainty. The robustness of the controller with respect to communication latency is also analyzed. </p> <p> Simulation and experimental studies demonstrate that the proposed approach is highly effective in all phases of a teleoperation task, i.e. in free motion and in contact with both flexible and rigid environments. </p> <p> The second approach involves finite-dimensional state-space models that incorporate the delay for free motion/ soft contact as well as rigid contact modes of operation. Local dynamic linearization control laws are employed to linearize robotic manipulators' dynamics. Model-based discrete-time Linear Quadratic Gaussian (LQG) controllers are proposed that can deliver a stable transparent response for each phase of operation. The robustness of these controllers with respect to parameter uncertainty is examined via the Nyquist analysis. Simulation results demonstrate the effectiveness of the proposed approach. </p> / Thesis / Master of Applied Science (MASc)

Finite element simulation of contact/impact problems using the penalty method is a well-established capability. The automatic penalty stiffness provides an easy way to implement the contact analysis. However, this way in which the penalty stiffness is associated with the material property and geometry of the master surface can lead to inappropriate distributions of contact pressure at edges or mesh transitions, or even cause much numerical noise. A new method of defining the penalty stiffness, which is associated with geometry of the slave surface, the reference penetration and reference contact pressure, is developed to consistently relate forces on contacting nodes with the contact pressure. This technique is successfully applied to several examples as the clamping simulation during the punch test and the rolling process. The results of such applications of new contact stiffness model demonstrate the effectiveness of such a model in avoiding the stress edge effect and the accompanying numerical noise. As an alternative approach to define the penalty stiffness, this new model provides another option for the contact analysis and gives the users more possibilities to control the contact performance. / Thesis / Master of Engineering (ME)

Master Gardener (MG) volunteers are nonpaid, education partners with Virginia Cooperative Extension (VCE). VCE MGs have assisted Extension agents in meeting VCE's educational goals and mission by following the Sustainable Landscape Management educational program objectives within the VCE Plan of Work. Local MG volunteer programs must be managed appropriately so that volunteers are prepared for their work, complete their volunteer jobs, and remain an active part of the local program. Prior to 1996, local agents trained and managed MG volunteers and supervised the projects in which MGs volunteered. Budgetary actions in 1996 transitioned management from state-funded agents to a system of local MG coordinators consisting of locally funded agents, locally funded non-agent coordinators, or volunteers willing to take on additional responsibilities. In order to provide consistent, state-level direction and leadership to this less experienced group of local coordinators and to prepare them for their jobs as MG program managers, current management materials were extensively revised and expanded and new resources were developed. These efforts to ensure that everyone understood the purpose and focus of the VCE MG program resulted in revision of MG program policies; development of new volunteer management materials, VCE publication 426-699 Welcome to Virginia Master Gardenering! Guide to Educational Programming and Resource and Reference Guide; establishment of a MG planning and work team; new management guidelines, the VCE Master Gardener Coordinator Manual; in-service training for coordinators; an administrative website at http://www.ext.vt.edu/vce/specialty/envirohort/mastergard/master.html; the VCE-MGC electronic discussion "listserv" specifically for direct communication with coordinators; and the Virginia Master Gardener Leadership Development Newsletter, the state MG newsletter refocused on the role of Master Gardeners as community leaders and educators. Evaluation of the VCE Master Gardener Coordinator Manual, a 14-chapter resource book developed cooperatively with teams of Master Gardeners (MG), coordinators, and agents to enhance coordinators' skills in managing the local VCE MG program, identified areas for enhancement prior to final publication. It showed that coordinators are using the manual. They are adapting the suggestions and samples to fit their local programs despite the fact that more planning time is often required. Use of the manual has also resulted in increased understanding of VCE goals and the role of the MG by MG volunteers, coordinators, and other paid VCE staff; a slight increase in leadership skills of MGs; and increasing interest and demand for information on training MG to design and implement strong educational horticulture programs for Virginia communities. An assessment of current MG management practices in Virginia measured the adoption of new VCE MG volunteer management guidelines. Results indicated that the MG management practices among local VCE MG coordinators have changed to that of a more professional, long-term relationship that is committed to nurturing the volunteer, the MG program, and VCE educational programming. These changes were noted in areas of volunteer management, such as the role of the local coordinator, use of job descriptions, recruitment, volunteer evaluation, public relations, reporting and record keeping, and retention of volunteers. Although the improvements in management practices were slight, they were encouraging and they indicate areas where state MG management must provide additional training and support to local coordinators. Annual assessment of local MG program management practices will continue to document the progress of local coordinators and determine necessary changes and training needed to achieve more professional, well-managed MG programs. / Master of Science

Syftet med studien var att undersöka vad lotsar, befälhavare och bogserbåtsbefälhavare ansåg om den verbala kommunikationen med hänsyn till säkerhet och effektivitet. Detta eftersom majoriteten av alla fartygsolyckor inträffar på grund av den mänskliga faktorn, där kommunikationen är en stor del. I studien genomfördes semistrukturerade intervjuer med två lotsar, två befälhavare och två bogserbåtsbefälhavare. Genom de sex intervjuerna i studien gick det bland annat att utläsa att användandet av standardfraser och closed loop communication varierar. Om användandet inom dessa två områden blev bättre skulle säkerheten kunna ökas. I studien framkom det också att kunskapen i eng­elska varierar vilket kan leda till missuppfattningar. Bättre kunskap i det engelska språket och hur man kommunicerar kan vara två andra sätt att öka säkerheten. / The aim of this study was to examine how pilots, vessel masters and tugboat masters perceive the importance of verbal communication with consideration to safety and efficiency.  This is based on the fact that the vast majority of accidents involving vessels occur because of human error, where lack of communication plays a large part. In the study semi-structured interviews were held with two pilots, two masters and two tugboat masters. After conducting these six interviews it became apparent at the use of standard phrasing and closed loop communication could vary. Based on the information collected one conclusion is that if the usage within these two areas improved safety could increase. It was also apparent in this study that the knowledge of the English language differed greatly which also could lead to misunderstandings with the giving of instructions. A better proficiency in English and better knowledge of verbal communication could be two possible ways of increasing safety.

CONTENTS vi Title: Implementation of parallel query processing in PostgreSQL Author: Bc. Daniel Vojtek Department: Department of Software Engineering Supervisor: Mgr. Július Štroffek Supervisor's e-mail address: julo@stroffek.cz Abstract: Parallel query processing can help with processing of huge amounts of data stored in database systems. The aim of this diploma the- sis was to explore the possibilities, analyze, design and finally implement parallel query processing in open source database system PostgreSQL. I used a Master/Worker design pattern, in which standard PostgreSQL backend process is a master. As workers I used processes created from postmaster. In the thesis I focused on preparing an infrastructure nec- essary for parallel processing. I defined a new top level memory context over shared memory, which allows efficient and convenient memory al- locations. Then I implemented creation of new worker processes, based on master process requirements. To be able to control these workers I defined controlling structures using state machines. Then I implemented parallel sort operation and SQL operator UNION ALL using this infras- tructure. The result of this diploma thesis is not only implementation of infrastructure and some parallel operations, but also description of the problems encountered during the...

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Quantitative descriptions of reaction kinetics formulated at the stochastic mesoscopic level are frequently used to study various aspects of regulation and control in models of cellular control systems. For this type of systems, numerical simulation offers a variety of challenges caused by the high dimensionality of the problem and the multiscale properties often displayed by the biochemical model. In this thesis I have studied several aspects of stochastic simulation of both well-stirred and spatially heterogenous systems. In the well-stirred case, a hybrid method is proposed that reduces the dimension and stiffness of a model. We also demonstrate how both a high performance implementation and a variance reduction technique based on quasi-Monte Carlo can reduce the computational cost to estimate the probability density of the system. In the spatially dependent case, the use of unstructured, tetrahedral meshes to sample realizations of the stochastic process is proposed. Using such meshes, we then extend the reaction-diffusion framework to incorporate active transport of cellular cargo in a seamless manner. Finally, two multilevel methods for spatial stochastic simulation are considered. One of them is a space-time adaptive method combining exact stochastic, approximate stochastic and macroscopic modeling levels to reduce the simualation cost. The other method blends together mesoscale and microscale simulation methods to locally increase modeling resolution. / eSSENCE

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