In the past 10 years, the bandwidths and processing capabilities of the networks have increased dramatically. The number of real-time applications using these networks has also increased. The large number of real-time packets might, in a switched multi-hop network, lead to unpredictable traffic patterns. This is not a problem when the traffic intensity is low, but if the same network is used by a large number of users simultaneously, the overall performance of the network degrades. In fact, unpredictable delays in the delivery of the message can adversely affect the execution of the tasks dependent on these messages, even if we take into account the soft real-time performance. In this paper, we investigate the effect of traffic shapers on soft real-time performance. We will consider a switched multi-hop network with FCFS queues. We will implement two versions of the network simulator. One version will be without traffic shaper and the other version will use a traffic shaper. By comparing the results (for average delay, deadline miss ratio etc.) from both the versions, we will try to conclude if it is really beneficial to use traffic shapers for soft real-time performance. Leaky bucket and token bucket algorithms are the most popular ones for traffic shaper implementation. We will consider leaky bucket algorithm for our analysis. We analyse different versions of the leaky bucket and present the trade-off’s involved.

The present work consists of three parts. In the first part (chapters III and IV), the dynamics of Lorentz lattice gases (LLG) on graphs is analyzed. We study the fixed scatterer model on finite graphs. A tight bound is established on the size of the orbit for arbitrary graphs, and the model is shown to perform a depth-first search on trees. Rigidity models on trees are also considered, and the size of the resulting orbit is established. In the second part (chapter V), we give a complete description of dynamics for LLG on the one-dimensional integer lattice, with a particular interest in showing that these models are not capable of universal computation. Some statistical properties of these models are also analyzed. In the third part (chapter VI) we attempt to partition a pool of workers into teams that will function as independent TSS lines. Such partitioning may be aimed to make sure that all groups work at approximately the same rate. Alternatively, we may seek to maximize the rate of convergence of the corresponding dynamical systems to their fixed points with optimal production at the fastest rate. The first problem is shown to be NP-hard. For the second problem, a solution for splitting into pairs is given, and it is also shown that this solution is not valid for partitioning into teams composed of more than two workers.

A fascinating feature of bucket brigade assembly lines is that work load on workers is balanced spontaneously as workers follow some simple rules in the assembly process. This self-organizing property significantly reduces the management effort on an assembly line. We generalize this idea in several directions. These include an adapted bucket brigade protocol for complex assembly networks, a generalized model that permits chaotic behavior, and a more detailed model for a flow line in which jobs arrive arbitrarily in time and are introduced into the system at several points on the line.

The increasing number of delay and loss critical services in packet networks require differentiated packet handling in the forwarding plane. Quality of Service (QoS) guarantees can be given for networks using resource reservation and admission control. However, such strategies require complex control plane extensions and might lead to higher operation expenditures. Network operators therefore often use over-provisioning and traffic differentiation to offer cheaper Class of Service (CoS) quality in their internet protocol (IP) packet networks. The number of differentiated classes and their autonomous system (AS) internal implementation is at the operator’s choice. This paper proposes a signalling concept for inter-AS layer three Class Set signalling, supported classes, their encoding and packet rate limitations. It makes use of the Border Gateway Protocol (BGP) as the predominantly used routing protocol for AS peering communication. The paper specifies two new nontransitive attributes, which enable adjacent peers to signal Class of Service capabilities and admission control limitations. The new "CoS Capability Attribute" and the “CoS Parameter Attribute" are simple data structures, which signal the classes, their per hop behaviour (PHB) ID code and the token bucket control performed at the ingress AS border router for rate limitation purposes. The denoted Class of Service forwarding support is meant as the AS externally available (transit) Class of Service support. The approach is now work in progress at the IETF.

Baigiamajame magistro darbe apžvelgti laboratoriniai ir praktiniai abrazyvinio dėvėjimosi tyrimų metodai. Sumontuotas ekskavatoriaus kaušo dantų abrazyvinio dėvėjimosi stendas, sudaryta nauja tyrimo metodika. Tyrimas buvo atliktas su šešiais ekskavatoriaus kaušo dantimis: trys aplydyti „Anykščių vario“, du ESAB firmų elektrodais, vienas dantis neaplydytas. Darbe ištirtos neaplydyto ir aplydytų skirtingais elektrodais ekskavatoriaus kaušo dantų abrazyvinio dėvėjimosi charakteristikos, pateiktos išvados ir rekomendacijos. / The final magistracy work review laboratory and field abrasive wear test methods. New excavator bucket teeth abrasive wear tester was mounted and new research method was created. Research was developed with six excavator bucket’s teeth: three teeth were coating with “Anyksciu varis” company electrodes, two teeth were coating with ESAB company electrodes and one tooth wasn’t coating. In this work are analysing teeth that are coating with several types electrodes or without them, abrasive wear performances. It was present conclusion and recommendation.

Secondary markets have not historically possessed the characteristics necessary for market power to emerge, or effective product differentiation to be implemented. The potential effects of these characteristics on primary – secondary market interaction is generally not considered. The law of one price is expected to hold in secondary markets. By applying the hedonic technique to producer theory, and integrating the durability of the product directly into the profit maximizing conditions, potential differences in implicit prices between customer segments in the used bucket truck market are estimated. Applying weighted least squares to the hedonic equation, parameters were estimated to indicate whether differences in hedonic prices exist between customer segments in the secondary, utility construction equipment market. The hedonic approach accounted for differences in price due to physical characteristics, while underlying supply and demand conditions were accounted for using indicator variables for time. Estimated differences in the effects of physical characteristics on price, between industries, were identified using interaction terms. Results of the econometric estimation indicate that differences in physical product characteristics do not fully account for differences in price between customer segments in the secondary bucket truck market. If the law of one price can be violated in a secondary market, this could indicate market power. Future research on primary – secondary market interaction should consider the potential effects, if such market power does indeed exist.

Orientador: Lizete Maria Orquiza de Carvalho / Banca: Roberto Nardi / Banca: João Zanetic / Resumo: É corrente entre os pesquisadores a necessidade de inserção de História. Filosofia e Sociologia da Ciência no ensino de ciências, assim como esta inserção é recorrentemente apontada como uma solução para a suposta crise que invadiu o ensino nesta modalidade. Insatisfeitos com o rumo que estas pesquisas estão tomando, delineamos nosso problema de pesquisa. Explicitamos nossa concepção de educação embasada principalmente pela obra do educador Paulo Freire, ou seja, apresentamos nossa concepção de educação dialógica-problematizadora na vertente emancipadora. Fazemos uma aproximação entre a concepção freiriana de educação e o ensino de ciências, a fim de estabelecer uma concepção de ensino de ciências, bem como do ensino de física do qual compartilhamos. Nessa concepção de ensino de ciências apresentamos a finalidade pela qual pretendemos resgatar a História, Filosofia e Sociologia da Ciência, HFSC, argumentando em favor de sua inseparabilidade com a Ciência no ensino de ciências. Apresentamos a Experiência do Balde de Newton e a finalidade que a mesma teria nessa concepção. Concluímos que a construção de enunciados sobre a experiência dp Balde de Newton, através de seus consequentes pronunciamentos e sua volta problematizada ao sujeito, proporcionou aos alunos uma transformação da realidade / Abstract: It is a common practi ce among researches the need of entering into History, Philosophy and Sociology of Science in science teaching, and this integration is repeatedly cited as a solution to the supposed crisis that broke into the school championship. Unhappy with the way these survey are taking, we delicated our research problem. We explicited our conception of education based mainly on the work of eductor Paulo Freire, that is, we present our vision of dialogic-problematizing education in the shed for liberation. We make a connection between the desing Freirien education and science education in order to establish a conception of science teaching and the teaching of physics which we share. In this conception of science education we present the purpose we intend redeem the History, Philosophy and Sociology of Science, HFSC, arguing for the inseparability of Science in science education. We present the experience of Newton's bucket and the the purpose that it would have this view. We conclude that the construction of statements about the experience of Newton's bucket through this consequent pronouncements and his return problematized to the subject gave the pupils a changing reality / Mestre

In semiarid regions, where water resources are limited and precipitation dynamics are changing, understanding land surface-atmosphere interactions that regulate the coupled soil moisture-precipitation system is key for resource management and planning. We present a modeling approach to study soil moisture and albedo controls on planetary boundary layer height (PBLh). We used Santa Rita Creosote Ameriflux and Tucson Airport atmospheric sounding data to generate empirical relationships between soil moisture, albedo, and PBLh. Empirical relationships showed that similar to 50% of the variation in PBLh can be explained by soil moisture and albedo with additional knowledge gained by dividing the soil profile into two layers. Therefore, we coupled these empirical relationships with soil moisture estimated using a two-layer bucket approach to model PBLh under six precipitation scenarios. Overall we observed that decreases in precipitation tend to limit the recovery of the PBL at the end of the wet season. However, increases in winter precipitation despite decreases in summer precipitation may provide opportunities for positive feedbacks that may further generate more winter precipitation. Our results highlight that the response of soil moisture, albedo, and the PBLh will depend not only on changes in annual precipitation, but also on the frequency and intensity of this change. We argue that because albedo and soil moisture data are readily available at multiple temporal and spatial scales, developing empirical relationships that can be used in land surface-atmosphere applications have great potential for exploring the consequences of climate change.

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Master thesis is dealing with issues and problems of packet queue management in high speed packet networks. Design implementation is made in VHDL hardware description language. In theoretical part of thesis are explained different types of mechanism used for providing quality of service in communication networks. Furthermore the brief description o VHDL, FPGA and framework Netcope Development Kit is a piece of theoretical part as well. The outcome of practical part contains a design, limiting packet queues based on Tocken Bucket mechanism. Design verification was made by simulations, synthesis and real implementation on smart NIC NFB-200G2QL. All kind of verificaion results are summerized in last three chapters.