Black Hawk Creek was included in the Iowa Department of Natural Resources (DNR) 303(d) list of impaired waters in 1998 due to non-point sources of fecal coliform bacteria. Water quality degradation in the stream network is also impacted by excess nutrients in surface runoff from cropped fields and pastures, sedimentation erosion of streambanks from the high volume of water flow following storm events, and the pulse of enriched groundwater drained into the streams from the subsurface tile network. Rotational grazing will replace the current continuous grazing management system. Implementation includes controlling both sides of Black Hawk Creek in the permanent pastures with electric fencing, installing reinforced controlled stream crossing sites, establishing a permanent clean water distribution system and enhancing the Kentucky bluegrass dominated pastures with three cool season naturalized grass and three legume species adapted to the north central Iowa loess landscape. Multi-species ripariain buffers based on the Leopold Center for Sustainable Agriculture's model and other models based on simulating the functionality of presettlement ecosystem savannah grassland will be created between monocultures of corn and soybean fields and the stream network. Follow on studies will monitor the effectiveness of a managed forage sward, riparian buffers, and natural healing of streambanks to mitigate excess nutrient movement into the streams. / Master of Natural Resources

Forestry is a major industry in Sweden and the most common method to harvest timber is to clear-cut large areas. Clear-cutting can alter multiple physical, chemical, and ecological characteristics of headwater streams. To minimize these effects, vegetated riparian ‘buffers zones’ are often spared along streams and lakes. Despite this, there are uncertainties regarding optimal width of buffers to safeguard streams from clearcutting effects. In this study, I ask how riparian buffer width influences stream macroinvertebrate communities, and how this influence may be altered by summer drought. I tested this in 24 headwater streams, half located in northern Sweden and the other half in southern Sweden. Streams in each region included four different buffer width categories (n = 3), including: “no buffer” (no trees left post-harvest), “thin buffer” (< 5 m), “moderate buffer” (> 5 m) and “reference” (no harvest). I analysed a suite of metrics that describe the abundance, richness, and composition of macroinvertebrates, and compared these across streams with different buffer properties. Regionally, southern streams had marginally greater taxonomic richness and relative abundance of sensitive taxa compared to northern counterparts, regardless of buffer conditions. Further, thin and absent buffers performed the best across several macroinvertebrate metrics, particularly for southern streams. Antecedent drought had no observable effects on macroinvertebrate communities, but taxonomic richness across region was positively correlated with stream pH. Overall, my findings, while tentative given low statistical power, suggest that retaining coniferous-dominated buffers may not lead to the desired ecological outcomes in boreal headwaters.

Conversion of natural grasslands for agricultural uses and intensification of agricultural production has been a major cause of natural ecosystem fragmentation and biodiversity loss. Diversifying agricultural landscapes by adding semi-natural grasslands can potentially help couple agricultural production (i.e., providing food, fiber, and energy to a growing human population) with environmental stewardship, enhancing ecosystem health, and increasing biodiversity. To ensure long-term ecological benefits of buffers and to maintain them as suitable habitat for prairie-associated species, periodic disturbance is required to keep buffers in an early-successional grassland plant community. In this dissertation, I fill knowledge gaps about biodiversity of semi-natural grassland buffers within agroecosystems. I investigate influence of prairie-history on buffer forb communities and effects of disking and burning on semi-natural grassland buffer plant and butterfly communities. I also investigate suitability of using butterflies as surrogates of birds and plants on semi-natural grassland buffers. Prairie-history influenced buffer forb communities, and disking increased forb richness and abundance. Disturbance guild butterflies responded positively to disking, most likely due to increased availability of nectar-rich plants. Grassland guild butterflies were not impacted negatively by disking or burning. Responses of plants and butterflies to disking and burning varied between sampling years. Effects of disking in fall 2007 persisted for two growing seasons, but I observed little effects of disking in fall 2008. Butterflies, with the possible exception of Pearl Crescent, were unsuitable as surrogates for birds. In contrast, butterflies, including Pearl Crescent, showed suitable or marginally suitable correlations with plants. Results of my study should help agricultural producers accomplish environmental conservation objectives and provide science-based information for developing and refining USDA practice standards and policy.

Optical packet switching networks are the foundation for next generation high speed Internet and are fast becoming the norm rather than an option. When such high speed optical networks are taken into account, one of the key considerations is packet buffering. The importance of packet buffering plays an even bigger role in optical networks because of the physical and technological constraints on the buffer sizes that can be implemented. Existing protocols, in many real world scenarios do not perform well in such networks. To eliminate such scenarios where there is a high possibility of packet loss, we use packet pacing. The proposed pacing scheme aims to reduce or eliminate packet losses arising from packet bursts in small-buffer networks. This thesis deals with a proposed hardware design and implementation of the packet pacing system on a NetFPGA. Our results show that the packet pacer can be implemented with a low overhead on hardware resources.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: End stop impact forces are horizontal longitudinal forces imposed by the crane on the end stops. Both the previous South African loading code SABS 0160:1989 and the current South African loading code SANS 10160 , classify end stop impact force as an accidental load case , hence they are not expected to occur within the expected lifetime when the guide lines for crane operation are strictly adhered to. In the estimation of end stop impact force, the previous South African loading code SABS 0160:1989 gives two guidelines for estimating the end stop impact force. The first guideline is simplistic in its approach and it’s based on the assumption that the crane and its supporting structure act as rigid bodies; hence calculation is based on rigid body mechanics. Literature reviewed reveals that this is not correct. The second guideline is more explicit in its approach as it takes into account the crane speed, resilience of the buffers and resilience of the end stops. The current South African loading code, SANS 10160 gives a better representation of the dynamics of the crane movement. However, the dynamic factor recommended for the estimation of end stop impact force is empirical in nature and thus lacks adequate scientific backing. One of the purposes of this research was to investigate the influence of the stiffness of the crane bridge on the end stop impact force. This was achieved by conducting a series of FEA simulations on the double bridge EOHTC fitted with elastomeric buffers. For this set of simulations, the effect of each influencing parameter on the end stop impact force was investigated, and the maximum end stop impact force was obtained using a constraint optimization technique. From the results obtained, comparison was then made with the existing maximum end stop impact force for a single bridge EOHTC fitted with elastomeric buffers. Another purpose of this research was to investigate the end stop impact force for an electric overhead travelling cranes (EOHTC) fitted with hydraulic buffers taking into account the dynamics involved in the movement of the EOHTC. This was achieved by a series of experimental and numerical investigation. The numerical investigation was conducted using an existing numerical model of an EOHTC which captures the crane and its supporting structure as a coupled system. Finite element analysis (FEA) impact force histories obtained were calibrated to the base experimental impact force histories. Thereafter, a series of FEA simulations were conducted by changing the parameters which have a substantial effect on the end stop impact forces. This yielded various maximum impact peaks for various parameters. The maximum impact force was then mathematical obtained from the FEA impact force histories for a given level of reliability using a constraint optimization technique. Also, codified end stop impact forces were calculated for the SABS 0160:1989 and SANS 10160-6:2010. From the results obtained, comparison was made between the codified end stop impact force and the maximum impact force obtained from the constraint optimization technique. / AFRIKAANSE OPSOMMING: Ent buffer impak kragte is horisontale kragte wat deur die kraan op die entbuffers aangewend word. Beide die Suid Afrikaanse las kode SABS 0160:1989 en die voorgestelde Suid Afrikaanse las kode SANS 10160, klasifisseer die entbuffer impak kragte as ‘n ongeluks las geval, dus word die kragte nie verwag tydens die verwagte leeftyd van die kraan wanneer die riglyne van die kraan prosedures streng gevolg word nie. Volgens die Suid-Afrikaanse las kode SABS 0160:1989 word daar twee riglyne voorgestel om die entbuffer kragte te bepaal. Die eerste riglyn is ‘n eenvoudige riglyn en word gebaseer op die aaname dat die kraan en die ondersteunende struktuur as ‘n starre ligame reageer en dus word die kragte bereken deur star ligaam meganika, alhoewel, uit die literatuur word dit bewys as inkorrek. Die tweede riglyn is ‘n meer implisiete benadering aangesien dit die kraan snelheid, elastisiteit van die buffers sowel as die elastisiteit van die end stoppe in ag neem. SANS 10160-6:2019 gee ‘n beter benadering van die dinamiese beweging van die kraan. Die voorgestelde dinamiese faktor waarmee die ent_buffer_kragte bereken word, is empiries van natuur . Een van die doelstellings vir die navorsings projek was om te bepaal wat die invloed van die kraan brug se styfheid op die entbuffer kragte is. ‘n Aantal Eindige Element Analise (FEA) simulasies is uitgevoer op ‘n dubbel brug elektriese aangedrewe oorhoofse kraan met elastomeriese buffers. Van die stel FEA simulasies kan die invloed van elke parameter op die entbuffer impak_kragte bepaal word. Die maksimum entbuffer impak_kragte is bepaal met behulp van ‘n beperking optimiserings tegniek. Vanaf hierdie resultate is ‘n vergelyking gemaak met die bestaande maksimum ent_buffer impak_kragte vir ‘n enkel brug elektriese oorhoofse aangdrewe kraan met elastomeriese buffers. ‘n Tweede doel rede vir die navorsing was om te bepaal wat die ent buffer impak_kragte op ‘n elektriese aangedrewe oorhoofse kraan met hidrouliese buffers is. Dit is bepaal deur ‘n aantal eksperimentele en numeriese toetse uit te voer. Die numeriese toetse is uitgevoer deur gebruik te maak van ‘n huidige numeriese model van ‘n elektriese aangedrewe oorhoofse kraan wat die kraan en die ondersteunende struktuur as ‘n. Die Eindige Element Analise impak_kragte is gekalibreer teen die eksperimenteel bepaalde impak- kragte. Daarna is ‘n reeks Eindige Element Analise simulasies uitgevoer en sodoende die parameters te verander wat die mees beduidende invloed op die end stop impak_kragte het. Dit het verskeie impak_krag pieke vir verskillende parameters meegebring. Die maksimum impak kragte is bepaal van die impak kragte van die Eindige Element Analise vir ‘n gegewe vlak van betroubaarheid deur gebruik te maak van die beperking optimiserings tegniek. Daarmee saam is die gekodifiseerde ent buffer impak kragte bereken volgen SABS 0160:1989 en die SANS 10160- 6:2010. Vanaf hierdie resultate is ‘n vergelyking gemaak tussen die gekodifiseerde entbuffer impak_kragte en die maksimum impak_kragte wat bepaal is deur die (beperking optimiserings tegniek).

Objetivo: Realizou-se um estudo, no período de 2002 a 2009, com a finalidade de verificar se as mudanças nas classes de cobertura da terra e no uso do solo podem exercer influência na ocorrência da raiva, nos municípios de Jacareí e de Santa Branca, situados na Região do Vale do Paraíba, no Estado de São Paulo, Sudeste do Brasil. Métodos: A ferramenta utilizada para avaliar estas alterações foi o sensoriamento remoto, através de imagens de satélite Land-sat. Para pesquisar a presença do vírus da raiva (RABV) foram coletados animais silvestres atropelados nas rodovias, morcegos encontrados na área urbana em atitude suspeita, morcegos hematófagos da espécie Desmodus rotundus e animais de interesse econômico (ADIE) que vieram a óbito por enfermidade com sintomatologia nervosa. O material coletado, sistema nervoso central (SNC), desses animais foi encaminhado para o laboratório de referência nacional, o Instituto Pasteur de São Paulo (IP-SP) e para o Laboratório de Sanidade Animal da Agência Paulista de Tecnologia dos Agronegócios (APTA)- Pólo Regional do Vale Paraíba (PRDTA/VP) - Pindamonhangaba-SP. A determinação da presença do antígeno viral foi feita através da prova de imunofluorescência direta (IFD) e o isolamento do vírus através da inoculação intracerebral em camundongos (IC). Os inóculos das amostras foram submetidos à prova de reação em cadeia pela polimerase transcriptase reversa (RT-PCR) para verificar a presença do vírus da raiva. Resultados: No período de estudo tivemos a ocorrência de dez casos da doença, sendo três em morcegos insetívoros na zona urbana de Jacareí, e sete em ADIE, sendo dois, em Jacareí e cinco, em Santa Branca. Todos os animais silvestres terrestres examinados foram negativos para a presença do vírus da raiva em todas as provas realizadas (IFD, IC, RT-PCR). O material proveniente dos morcegos foi negativo para as provas de IFD e IC, porém três amostras, oriundas de morcegos insetívoros, resultaram positivas para a prova de RTPCR. As amostras de ADIE examinadas resultaram positivas para todas as provas realizadas. O sequenciamento genético utilizou amplificações referentes à glicoproteína viral das 8 amostras positivas para rt-pcr, obtendo para os cinco isolados de ADIE linhagem de desmodus rotundus e para os três isolados de morcegos linhagens de nyctinomops laticaudatus e tadarida brasiliensis. Quando foi estudada a cobertura do solo e seu uso, considerando os municípios, constatou-se que não haviam ocorrido mudanças significativas entre 2002 e 2009. Optou-se por fazer buffers de raio de 3 km tendo como centro de cada buffer as coordenadas geográficas de casos positivos para raiva. Como em duas situações houve sobreposição entre áreas de buffers, resolveu-se considerar a área da união dos mesmos. Foi interessante que, mesmo nestes buffers não houve mudanças significativas, apesar da ocorrência da doença. Conclusão: Na escala utilizada, considerada micro, a enfermidade aconteceu, mesmo sem mudanças aparentes na região. Provavelmente, em uma escala macro outros resultados poderiam ser obtidos / Objective: This study was carried out during the period of 2002-2009, with the purpose to verify whether the changes in types of land cover and in land use can influence the occurrence of rabies in Jacareí and Santa Branca, situated in the Vale do Paraíba, State of São Paulo, southeastern brazil. Methods: The tool used to evaluate these alterations was the remote sensing through images of satellite land-sat. In order to search for the presence of rabies virus, brain materials were collected from wild animals roadkilled in highways, bats found in the urban area in suspicious attitude, desmodus rotundus hematophagous bats captured in rural areas and farm animals of economic importance (aei) dead with suspect of rabies. For rabies diagnosis, specimens of central nervous system (cns) of these animals were sent to the Pasteur Institute of São Paulo (IP-SP) - national reference laboratory and to the laboratory of animal Paulista Agency for Agribusiness Technology (APTA) - Polo Valley Regional of Paraíba (PRDTA / VP), in Pindamonhangaba, state of SP. The presence of viral antigen was determined by the direct fluorescent antibody technique (D-FAT) and the isolation of the virus by means of intracerebal mouse inoculation test (MIT). The brain suspensions were submitted to reverse transcriptase. Polymerase chain reaction to check the presence of rabies virus. Results: In the period of study, 10 positive cases were detected, being 3 in insectivorous bats in the urbane zone of jacareí, and 7 in aei, being 2 in jacareí and 5 in santa branca. All the terrestrial wild animals examined were negative for the presence of rabies virus in all tests performed (d-fat, mit, and rt-pcr). The materials from bats were found negative for the d-fat and mit, however, three samples originating from insectivorous bats turned out to be positive for rt-pcr. The positive samples from aei were positive for all tests carried out. The genetic sequencing of the g gene of eight rt-pcr positive rabies virus isolates derived from aie, five corresponded to the desmodus rotundus lineage and the three bat isolates were related to lineages of nyctinomops laticaudatus and tadarida brasiliensis. When land coverage and its use were analyzed, considering the municipalities, it was found that no significant changes occurred between 2002 and 2009. Then buffers of 3 km in radius were chosen taking as the center of each buffer the geographical coordinates of positive rabies cases. Since in two situations there was superposition between areas of buffers, it was resolved to consider the junction area of the buffers. Even in these buffers there was no significant change, despite the occurrence of the disease. Conclusion: it was concluded that the disease has occurred even without any apparent changes in the region, due to the (micro) scale used in this study. Probably, in a macro scale, other results might be obtained

Made available in DSpace on 2016-06-02T19:53:31Z (GMT). No. of bitstreams: 1 LUGO_Pedro_2013.pdf: 2147400 bytes, checksum: a0c7948826b7f243c447b99fd96c3388 (MD5) Previous issue date: 2013-09-12 / Financiadora de Estudos e Projetos / This research studies the hybrid flowshop scheduling problem. In this production configuration, we have a set of jobs that has to be processed in a set of stages. At every stage we have a set of parallel machines available to process the jobs. All jobs have to be processed following the same production flow, from the first to the last stage. Every job has to be processed on one machine at each stage and each machine can process at most one job at a time. Some constraints commonly found in real production systems as unrelated parallel machines, limited buffers, sequence-dependent setup times (both anticipatory and non-anticipatory), machine eligibility, transportation times and release times for machines are also taken into account. The optimization criterion is the makespan, whose minimization is related to the efficient use of production resources. A mixed integer programming model is proposed and solved by the commercial solver CPLEX. The computational evaluation results indicate that the model is suitable just to solve instances up to nine jobs and five stages. Therefore, to solve larger instances (50-100 jobs), several heuristics and an iterated local search (ILS) algorithm are proposed and evaluated computationally. The results indicate that the ILS is able to obtain good quality solutions in short computation times. / Este trabalho estuda o problema de programação da produção em sistemas Flowshop híbrido. Nesta configuração de produção há um conjunto de tarefas que deve ser processado em um conjunto de estações, nas quais um determinado número de máquinas paralelas encontra-se disponível para o processamento das tarefas. Todas as tarefas devem ser processadas seguindo o mesmo fluxo de produção, desde a primeira até a última estação. Cada tarefa deve ser processada em uma máquina de cada estação e cada máquina pode processar, no máximo, uma tarefa por vez. Algumas restrições comumente encontradas em sistemas de produção reais, como máquinas paralelas não relacionadas, buffers limitados, tempos de preparação dependentes da sequência (antecipatórios e não antecipatórios), elegibilidade de máquinas, tempos de transporte e tempos de liberação das máquinas, também são consideradas. O critério de otimização é o makespan, cuja minimização está diretamente relacionada com a utilização eficiente dos recursos de produção. Um modelo de programação inteira mista é proposto e resolvido através do solver comercial CPLEX. Os resultados da avaliação computacional indicam que o modelo é viável somente para resolver instâncias de até nove tarefas e cinco estações. Desta forma, para resolver instâncias de maior tamanho (50-100 tarefas), várias heurísticas e uma meta-heurística de busca local iterada (ILS, Iterated Local Search) são propostas e avaliadas computacionalmente. Os resultados indicam que o ILS é capaz de obter soluções de boa qualidade em curtos tempos computacionais.

Objetivo: Realizou-se um estudo, no período de 2002 a 2009, com a finalidade de verificar se as mudanças nas classes de cobertura da terra e no uso do solo podem exercer influência na ocorrência da raiva, nos municípios de Jacareí e de Santa Branca, situados na Região do Vale do Paraíba, no Estado de São Paulo, Sudeste do Brasil. Métodos: A ferramenta utilizada para avaliar estas alterações foi o sensoriamento remoto, através de imagens de satélite Land-sat. Para pesquisar a presença do vírus da raiva (RABV) foram coletados animais silvestres atropelados nas rodovias, morcegos encontrados na área urbana em atitude suspeita, morcegos hematófagos da espécie Desmodus rotundus e animais de interesse econômico (ADIE) que vieram a óbito por enfermidade com sintomatologia nervosa. O material coletado, sistema nervoso central (SNC), desses animais foi encaminhado para o laboratório de referência nacional, o Instituto Pasteur de São Paulo (IP-SP) e para o Laboratório de Sanidade Animal da Agência Paulista de Tecnologia dos Agronegócios (APTA)- Pólo Regional do Vale Paraíba (PRDTA/VP) - Pindamonhangaba-SP. A determinação da presença do antígeno viral foi feita através da prova de imunofluorescência direta (IFD) e o isolamento do vírus através da inoculação intracerebral em camundongos (IC). Os inóculos das amostras foram submetidos à prova de reação em cadeia pela polimerase transcriptase reversa (RT-PCR) para verificar a presença do vírus da raiva. Resultados: No período de estudo tivemos a ocorrência de dez casos da doença, sendo três em morcegos insetívoros na zona urbana de Jacareí, e sete em ADIE, sendo dois, em Jacareí e cinco, em Santa Branca. Todos os animais silvestres terrestres examinados foram negativos para a presença do vírus da raiva em todas as provas realizadas (IFD, IC, RT-PCR). O material proveniente dos morcegos foi negativo para as provas de IFD e IC, porém três amostras, oriundas de morcegos insetívoros, resultaram positivas para a prova de RTPCR. As amostras de ADIE examinadas resultaram positivas para todas as provas realizadas. O sequenciamento genético utilizou amplificações referentes à glicoproteína viral das 8 amostras positivas para rt-pcr, obtendo para os cinco isolados de ADIE linhagem de desmodus rotundus e para os três isolados de morcegos linhagens de nyctinomops laticaudatus e tadarida brasiliensis. Quando foi estudada a cobertura do solo e seu uso, considerando os municípios, constatou-se que não haviam ocorrido mudanças significativas entre 2002 e 2009. Optou-se por fazer buffers de raio de 3 km tendo como centro de cada buffer as coordenadas geográficas de casos positivos para raiva. Como em duas situações houve sobreposição entre áreas de buffers, resolveu-se considerar a área da união dos mesmos. Foi interessante que, mesmo nestes buffers não houve mudanças significativas, apesar da ocorrência da doença. Conclusão: Na escala utilizada, considerada micro, a enfermidade aconteceu, mesmo sem mudanças aparentes na região. Provavelmente, em uma escala macro outros resultados poderiam ser obtidos / Objective: This study was carried out during the period of 2002-2009, with the purpose to verify whether the changes in types of land cover and in land use can influence the occurrence of rabies in Jacareí and Santa Branca, situated in the Vale do Paraíba, State of São Paulo, southeastern brazil. Methods: The tool used to evaluate these alterations was the remote sensing through images of satellite land-sat. In order to search for the presence of rabies virus, brain materials were collected from wild animals roadkilled in highways, bats found in the urban area in suspicious attitude, desmodus rotundus hematophagous bats captured in rural areas and farm animals of economic importance (aei) dead with suspect of rabies. For rabies diagnosis, specimens of central nervous system (cns) of these animals were sent to the Pasteur Institute of São Paulo (IP-SP) - national reference laboratory and to the laboratory of animal Paulista Agency for Agribusiness Technology (APTA) - Polo Valley Regional of Paraíba (PRDTA / VP), in Pindamonhangaba, state of SP. The presence of viral antigen was determined by the direct fluorescent antibody technique (D-FAT) and the isolation of the virus by means of intracerebal mouse inoculation test (MIT). The brain suspensions were submitted to reverse transcriptase. Polymerase chain reaction to check the presence of rabies virus. Results: In the period of study, 10 positive cases were detected, being 3 in insectivorous bats in the urbane zone of jacareí, and 7 in aei, being 2 in jacareí and 5 in santa branca. All the terrestrial wild animals examined were negative for the presence of rabies virus in all tests performed (d-fat, mit, and rt-pcr). The materials from bats were found negative for the d-fat and mit, however, three samples originating from insectivorous bats turned out to be positive for rt-pcr. The positive samples from aei were positive for all tests carried out. The genetic sequencing of the g gene of eight rt-pcr positive rabies virus isolates derived from aie, five corresponded to the desmodus rotundus lineage and the three bat isolates were related to lineages of nyctinomops laticaudatus and tadarida brasiliensis. When land coverage and its use were analyzed, considering the municipalities, it was found that no significant changes occurred between 2002 and 2009. Then buffers of 3 km in radius were chosen taking as the center of each buffer the geographical coordinates of positive rabies cases. Since in two situations there was superposition between areas of buffers, it was resolved to consider the junction area of the buffers. Even in these buffers there was no significant change, despite the occurrence of the disease. Conclusion: it was concluded that the disease has occurred even without any apparent changes in the region, due to the (micro) scale used in this study. Probably, in a macro scale, other results might be obtained

[pt] Redes ópticas convencionais exigem conversão eletro-óptica em cada nó para roteamento adequado dos pacotes. Adicionalmente, recursos de gerenciamento relevantes são requisitados para auxiliar o roteamento. Neste trabalho, inteligência e funcionalidade são introduzidas na camada física de redes ópticas com topologia em malha de modo a prover um esquema eficiente de roteamento de portadoras ópticas e endereçamento de pacotes. No arranjo apresentado ocorre que: (a) nenhuma conversão optoeletrônica (O/E/O) torna-se necessária, exceto nos nós fonte e destinação; (b). recursos de gerenciamento são praticamente dispensados na camada física. Ao representar a rede por grafos, critérios de custo mínimo são atingidos. Em seguida, utilizam-se algoritmos que, em consonância com os custos mínimos, levam ao roteamento. A conectividade desejada é então introduzida, com os algoritmos seguindo a técnica de reutilização de capacidade dentro um mesmo comprimento de onda. Desta forma, os caminhos de luz são determinados englobando todos os pares de nós da rede. Chamamos este arranjo de SWRA (Smart Wavelength Routing Assignment) dado que cada portadora segue de forma passiva seu exato caminho na rede. A implicação é a sensível redução nos custos, tanto pelo lado dos conversores O/E/O, bem como pelo lado do gerenciamento da rede. Demonstra-se que este arranjo pode estar sujeito a colisão de dados em uma mesma portadora. Uma solução é apresentada pela introdução de buffers elétricos de baixo custo, dimensionados através de ferramentas estatísticas. / [en] In conventional optical networks, optoelectronic conversions are needed in each node for the sake of a proper packet routing. Simultaneously, intensive managing resources should be allocated to accomplish the routing task. The correct introduction of intelligence and functionality within the network physical layer may lead to some advantages over conventional networks. Two advantages are worthwhile be mentioning (a)-no optoelectronic conversions (O/E/O) are needed, except for the source and destination nodes, and (b)-management resources are practically unnecessary within the physical layer. As the network uses a graph representation, it is possible to reach minimal cost criteria. Next, coping with the minimal cost, suitable algorithms are used for proper wavelength routing. The desired connectivity is introduced, and the algorithms will lead to the technique of capacity reuse within the wavelength. In this way, light-paths are obtained, linking all network node pairs. We called this arrangement as SWRA (Smart Wavelength Routing Assignment), since within the network each wavelength follows its precise path in a passive way. The result appears as a significant cost reduction, which reflects the lack of O/E/O converters and on the use of less management gear. However, this arrangement may suffer occasional data collision within any wavelength. Hence, a solution to avoid this impairment is presented and described, using low-cost electric buffers. Additionally, the statistical evaluation of those buffers is supplied. / [es] Redes ópticas convencionales exigen conversión eletro- óptica en cada nodo para un adequado ruteamiento de los paquetes. Adicionalmente, se necesitan recursos relevantes de gerenciamiento para auxiliar el ruteamiento. En este trabajo, inteligencia y funcionalidad son introducidas en la camada física de redes ópticas con topología en malla a fin de proporcionar un esquema eficiente de roteamiento de portadoras ópticas y direccionamiento de paquetes. En el arreglo presentado sucede que: (a) no es necesaria ninguna conversión optoeletrónica (O/E/O), excepto en los nodos fuente y destino; (b). recursos de gerenciamiento son prácticamente dispensados en la camada física. Al representar la rede por grafos, es posible alcanzar criterios de costo mínimo. Enseguida, se utilizan algoritmos que, en consonancia con los costos mínimos, conducen al roteamiento. La conectividad deseada se introduce con los algoritmos siguiendo la técnica de reutilización de la capacidad dentro de la misma longitud de onda. De esta forma, los caminos de luz se determinan englobando todos los pares de nodos de la red. Este arreglo se denomina SWRA (Smart Wavelength Routing Asignment) dado que cada portadora sigue de forma pasiva su exacto camiño en la red. La implicación de este procedimento es uma sensible reducción de los costos, tanto por el lado de los conversores O/E/O, así como por el lado del gerenciamiento de la red. Se demuestra que este arreglo puede estar sujeto a colisión de dados en una misma portadora. Se presenta una solución introduciendo buffers eléctricos de bajo costo, dimensionados a través de herramientas estadísticas.

Monitoring of computer networks is central to ensuring that they function as intended, with solutions based on SNMP being used since the inception of the protocol. SNMP is however increasingly being challenged by solutions that, instead of requiring a request-response message flow, simply send information to a central collector at predefined intervals. These solutions are often based on Protobuf and gRPC, which are supported and promoted by equipment manufacturers such as Cisco, Huawei, and Juniper. Two models exist for monitoring. The pull model used by SNMP where requests are sent out in order to retrieve data, has historically been widely used. The push model, where data is sent at predefined intervals without a preceding request, is used by the implementations using Protobuf and gRPC. There is a perceived need to understand which model more efficiently uses bandwidth and the monitored system’s memory and processing resources. The purpose of the thesis is to compare two monitoring solutions, one being SNMP, and one based on Protobuf and gRPC. This is done to determine if one solution makes more efficient use of bandwidth and the system resources available to the network equipment. This could aid those who operate networks or develop monitoring software in determining how to implement their solutions. The study is conducted as a case study, where two routers manufactured by Cisco and Huawei were used to gather data about the bandwidth, memory, and CPU utilisation of the two solutions. The results of the measurements show that when retrieving information about objects that have 1-byte values SNMP was the better performer. When objects with larger values were retrieved SNMP performed best until 26 objects were retrieved per message. Above this point the combination of Protobuf and gRPC performed better, resulting in fewer bytes being sent for a given number of objects. No impact on the memory and CPU utilisation in the routers was shown. / Övervakning av nätverk är av yttersta vikt för att säkerställa att de fungerar som tänkt. Lösningar baserade på SNMP har använts sen protokollet kom till. SNMP utmanas mer och mer av lösningar som, istället för att använda ett meddelandeflöde baserat på fråga-svar, helt enkelt sänder information till en insamlande enhet i fördefinierade intervall. Dessa lösningar baseras ofta på Protobuf och gRPC, vilka stöds och propageras för av bland andra utrustningstillverkarna Cisco, Huawei, och Juniper. Två modeller för övervakning finns. Pull-modellen där frågor skickas ut för att hämta data, används av SNMP och har historiskt sett använts i stor skala. Push- modellen, där data skickas i fördefinierade intervall utan föregående fråga, används av lösningar som använder Protobuf och gRPC. Det finns ett behov av att förstå vilken modell som på ett mer effektivt sätt använder bandbredd och de övervakade systemens minnes- och processorresurser. Syftet med denna rapport är att jämföra två övervakningslösningar. SNMP är den ena lösningen, och den andra lösningen är baserad på Protobuf och gRPC. Detta i syfte att utröna om endera lösning på ett mer effektivt sätt använder bandbredd och systemresurser i nätverksutrustning. Detta kan hjälpa nätverksoperatörer och utvecklare av mjukvara för övervakning att avgöra hur dessa bör implementeras. För att besvara detta används en fallstudie, där två routrar tillverkade av Cisco och Huawei används för att samla in data om de två lösningarnas användning av bandbredd, minne, och processorkraft. Mätningarnas resultat visade att när objekt vars värde var 1 byte hämtades så presterade SNMP bättre. När objekt vars värden var större hämtades presterade SNMP bäst tills 26 objekt hämtades per meddelande. Därefter presterade kombinationen Protobuf och gRPC bättre, och krävde färre bytes för att skicka information om ett givet antal objekt. Ingen påverkan på minnes- eller processoranvändningen i routrarna påvisades av mätresultaten.