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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Programação de múltiplos cross-docks com múltiplas docas / Multiple cross-docks with multiple docks scheduling

Pâmella Sátiko Miyazaki Tenório 01 July 2016 (has links)
Cadeias de suprimentos podem ter operações seguindo diferentes estratégias de distribuição e a utilização de cada uma dessas estratégias pode resultar em diferentes operações e custos. A estratégia de cross-docking auxilia na redução dos custos de distribuição de produtos, consolidando cargas, e a redução de tempo e custos de armazenamento, uma vez que o tempo máximo de estoque permitido pela estratégia é de cerca de 24 horas. O objetivo deste trabalho é apresentar um modelo para o problema de cross-docking, em que cargas são entregues e reorganizadas de forma a atender a outras cargas que são coletadas e garantir que as janelas de tempo para início das operações sejam atendidas. Devido à falta de instâncias para o problema disponíveis na literatura, buscou-se gerar um benchmark e disponibilizá-las à comunidade científica. Uma vez que o problema é de difícil solução exata, um método heurístico para a resolução do problema foi desenvolvido. Os resultados mostraram que o modelo proposto resulta em boas soluções quando comparado ao modelo da literatura. O estudo de calibração do software IBM CPLEX mostrou que a calibração dos parâmetros pode resultar em melhores soluções e, por fim, a matheurística se mostrou competitiva com o CPLEX, principalmente para cenários em que a proporção de entregas e coletas diverge. / Supply chains may have operations which follow different distribution strategies and each one of these strategies may result in different operations and costs. The Cross-docking strategy helps to reduce the products distribution costs by consolidating loads and reducing storage costs as the maximum inventory time is approximately 24 hours. The aim of this research is to present a model for the cross-docking problem where loads are delivered and reorganized so as to cater for other loads that are collected and ensure that time windows are respected. Due to the lack of instances available in the literature, a benchmark was generated and was made available to the scientific community. As the problem is difficult to obtain the exact solution, a heuristic method was developed. The results showed that the proposed model has good solutions when compared to the literature model. A study of the IBM CPLEX software showed that tuning can result in better solutions and the matheuristcs was competitive with the software, mainly in scenarios where deliveries and pickups are very different.
72

Auto-organização da população em sistemas imunológicos artificiais aplicada ao docking de proteínas / Self-organization of population in Artificial Immune Systems applied to the protein docking

Helder Ken Shimo 17 July 2012 (has links)
Vários problemas do mundo real podem ser analisados como problemas de otimização. Na bioinformática, em especial, como exemplos podem ser citados o alinhamento múltiplo de sequências, a filogenia, a predição de estruturas de proteínas e RNA, entre outros. As Meta-heurísticas Populacionais (MhP) são técnicas baseadas em interações de conjuntos de soluções candidatas, como elementos de uma população, utilizadas na otimização de funções. Seu uso é especialmente interessante na otimização de problemas onde há conhecimento parcial ou nenhum do espaço de busca. O objetivo deste trabalho é investigar o uso de auto-organização da população de um sistema imunológico artificial (AIS) a fim de aplicá-lo no problema de docking, que pode ser visto como um problema de otimização multimodal complexo. O AIS é um tipo de MhP inspirado na microevolução do sistema imunológico adaptativo de organismos complexos. Neste, as soluções candidatas representam células do sistema imunológico que busca se adaptar para a eliminação de um patógeno. O desenvolvimento do algoritmo foi baseado no opt-aiNet, que utiliza dos princípios das teorias de seleção clonal e maturação de afinidade para realizar a otimização de funções. Adicionalmente, o opt-aiNet, inspirado na teoria de redes imunológicas, realiza uma etapa de supressão, que busca eliminar soluções semelhantes, aumentando assim a diversidade populacional. Esta etapa é computacionalmente custosa, dado que é feito o cálculo da distância entre todos os possíveis pares de células (soluções) afim de eliminar aquelas próximas de acordo com um dado critério. A proposta deste trabalho é o desenvolvimento de um algoritmo de supressão auto-organizável, inspirado no fenômeno da criticalidade auto-organizada, buscando diminuir a influência da seleção de parâmetros e a complexidade da etapa de supressão. O algoritmo proposto foi testado em um conjunto de funções contínuas conhecidas e comumente utilizadas pela comunidade de computação evolutiva. Os resultados obtidos foram comparados com aqueles de uma implementação do opt-aiNet. Em adição, foi proposta a utilização de operadores de mutação com distribuição q-gaussiana nos AISs desenvolvidos. O algoritmo foi também aplicado no problema de docking rígido baseado em complementaridade de superfícies e minimização de colisões, especificamente no docking de proteínas. Os resultados foram comparados com aqueles de um algoritmo genético, resultando em um melhor desempenho obtido pelo algoritmo proposto. / Many real world problems can be described as optimization problems. In bioinformatics in special, there is multiple sequence alignment, filogeny and RNA and Protein structure prediction, among others. Population based metaheuristics are techniques based in the interaction of a set of candidate solutions as elements of a population. Its use is specially interesting in optimization problems where there is little or no knowledge of the search space. The objective of this work is to study the use of self-organization of population in an artificial imune system for use in the docking problem, considered a complex multimodal optimization problem. The artificial imunme system is a type of population based methaheuristics inspired in the microevolution of the adaptive immune system of complex organisms. Candidate solutions represent cells of the immune system adapting its antibodies to eliminate a pathogen. The development of the algorithm was based in the opt-aiNet, based in the principles of clonal selection and affinity maturation for function optimization. Additionally, the opt-aiNet, inspired in theories of immune network, makes a suppression stage to eliminate similiar solutions and control diversity. This stage is computationally expensive as it calculates the distance between every possible pair of cells (solutions) eliminating those closer than a threshold. This work proposes a self-organized suppression algorithm inspired in the self-organized criticality, looking to minimize the influence of parameter selection and complexity of the suppression stage in opt-aiNet. The proposed algorithm was tested in a set of well-known functions in the evolutionary computation community. The results were compared to those of an implementation of the opt-aiNet. In addition, we proposed a mutation operator with q-Gaussian distribution for the artificial immune systems. The algorithm was then applied in the rigid protein docking problem based in surface complementarity and colision avoidance. The results were compared with a genetic algorithm and achieved a better performance.
73

Synaptic fluctuations in cerebellar interneurons connected by a single synaptic contact / Fluctuations synaptiques dans interneurones cérébelleux connectées par un contact synaptique unique.

Pulido Puentes, María Camila 11 March 2016 (has links)
L’élément constitutif des synapses centrales est le site synaptique individuel, comprenant une zone active du côté présynaptique et une densité postsynaptique associée. Du fait de limitations techniques nos connaissances sur le mode de fonctionnement d’un site synaptique restent insuffisantes. Pour faire progresser cette question nous projetons d’effectuer des enregistrements en paires entre interneurones de la couche moléculaire du cervelet. Ces neurones forment des synapses qui ont des signaux élémentaires quantiques de grande taille, et les synapses comprennent parfois un seul site synaptique, ce qui fait qu’ils offrent des avantages décisifs pour ce projet. Les réponses postsynaptiques à des trains de potentiels d’action seront étudiées dans différentes conditions expérimentales. Les résultats seront interprétés par un modèle supposant que les vésicules synaptiques doivent se lier à un petit groupe de sites d’arrimage avant l’exocytose. / The unitary element of central synaptic transmission is a single synaptic site, with one active zone as presynaptic component and the postsynaptic density as postsynaptic partner. Due to technical limitations there is much uncertainty on the mode of functioning of a single synaptic site. To address this issue it is planned to perform paired recordings between interneurons of the molecular layers of the cerebellum. These neurons form synapses with a large quantal size, and occasionally displaying a single release site, and are thus favorable for this study. Postsynaptic responses will be studied in response to trains of presynaptic action potentials under various conditions. The results will be compared to a model supposing the obligatory binding of vesicles to a small complement of docking sites prior to exocytosis.
74

Estudos in vitro sobre a atividade anti-helmíntica de lignanas extraídas da piper cubeba e in sílico com as proteínas β-tubulina e fosfoetanolamina metil transferase do haemonchus contortus /

Féboli, Aline. January 2020 (has links)
Orientador: Rosangela da Silva Laurentiz / Resumo: O estudo sobre o uso de plantas e metabolitos secundários tem sido uma das alternativas mais estudadas nos últimos anos como forma de controlar a parasitose em ovinos provocada principalmente pelo nematoide Haemonchus contortus. A Piper cubeba é uma pimenta asiática que apresenta uma série de propriedades biológicas, incluindo atividade antiparasitária, sendo essa atividade, muitas vezes atribuida às lignanas cubebina, hinoquinina e diidrocubebina, que estão presentes na planta em maior concentração. Estudos in vitro com o extrato da Piper cubeba e com as lignanas cubebina, dihidrocubebina e hinoquinina demonstraram que esses compostos apresentam importante ação contra os vários estágios do desenvolvimento de vida do nematoide Haemonchus contortus, sendo a hinoquinina a mais eficaz (CE50 = 68 μg / mL contra ovos, CE50 < 35 μg / mL contra o estágio L1 e CE50 = 0.34 μg / mL contra o estágio L3). Devido à relevância desses resultados foram então realizados estudos de docking molecular com essas lignanas com o objetivo de avaliar a ação desses compostos com as proteínas fosfoetanolamina metil transferase (FMT) e a proteína tubulina do H. contortus usando o albendazol como fármaco de referência. O estudo de docking consensual utilizou os softwares Maestro 10.1, GOLD 5.3 e Autodock 4.2. Os resultados in sílico quando comparados aos resultados in vitro, demonstraram que o mecanismo de ação da hinoquinina, que se mostrou mais ativa, pode estar relacionado à inibição, tanto da β-tubul... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The study on the use of plants and special metabolites has been one of the most studied alternatives in recent years as a way to control parasitosis in sheep caused mainly by the nematode Haemonchus contortus. Piper cubeba is an Asian pepper that has a series of biological properties, including antiparasitic activity, and this activity is often attributed to cubebin, hinokinin and dihydrocubebin lignans, which are present in the plant in greater concentration. In vitro studies with the Piper cubeba extract and with the lignans cubebin, dihydrocubebina and hinokinin demonstrated that these compounds present important action against the several stages of the development of life of the Haemonchus contortus, being the hinokinin the most effective (EC50 = 68 μg / mL against eggs, EC50 <35 μg / mL against stage L1 and EC50 = 0.34 μg / mL against stage L3). Due to the relevance of these results, molecular docking studies were then carried out with these lignans in order to evaluate the action of these compounds with the phosphoethanolamine methyl transferase (FMT) proteins and the H. contortus tubulin protein using albendazole as a reference drug. The consensual docking study used the Maestro 10.1, GOLD 5.3 and Autodock 4.2 softwares. The in silico results when compared to the in vitro, demonstrated that the mechanism of action of hinokinin, which was more active, may be related to the inhibition of both β-tubulin and FMT-2. Although more research is needed, the results indicate tha... (Complete abstract click electronic access below) / Doutor
75

Computational modeling of protein-protein and protein-peptide interactions

Porter, Kathryn 30 August 2019 (has links)
Protein-protein and protein-peptide interactions play a central role in various aspects of the structural and functional organization of the cell. While the most complete structural characterization is provided by X-ray crystallography, many biological interactions occur in complexes that will not be amenable to direct experimental analysis. Therefore, it is important to develop computational docking methods that start from the structures of component proteins and predict the structure of their complexes, preferably with accuracy close to that provided by X-ray crystallography. This thesis details three applications of computational protein modeling, including the study of antibody maturation mechanisms, and the development of protocols for peptide-protein interaction prediction and template-based modeling of protein complexes. The first project, a comparative analysis of docking an antigen structure to antibodies across a lineage, reveals insights into antibody maturation mechanisms. A linear relationship between near-native docking results and changes in binding free energy is established, and used to investigate changes in binding affinity following mutation across two antibody-antigen systems: influenza and anthrax. The second project demonstrates that a motif-based search of available protein crystal structures is sufficient to adequately represent the conformational space sampled by a flexible peptide, compared to that of a rigid globular protein. This observation forms the basis for a global peptide-protein docking protocol that has since been implemented into the Structural Bioinformatics Laboratory’s docking web server, ClusPro. Finally, as structure availability remains a roadblock to many studies, researchers turn to homology modeling, in which the desired protein sequence is modeled onto a related structure. This is particularly challenging when the target is a protein complex, further restricting template availability. To address this problem, the third project details the development of a new template-based modeling protocol to be integrated into the ClusPro server. The implementation of a novel template-based search enables users to model both homomeric and heteromeric complexes, greatly expanding ClusPro server functionality. / 2020-08-30T00:00:00Z
76

Návrh dokovací stanice pro mobilní robot / Design of docking station for mobile robot

Obšil, Tomáš January 2018 (has links)
The aim of this diploma thesis is design of docking station for an autonomous mobile robot Breach. The task of docking station is to connect this robotic device to power supply without human intervention in order to charge its batteries. The theoretical part of diploma thesis contains research study about autonomous charging of robots. After that it is assessed suitability of using different types of docking stations and it was chosen optimal solution. The practice part of diploma thesis contains design of docking mechanism, which takes account of inaccurate navigation of robot with deviation of several centimeters. One part of this design deals with connector system, which is dimensioned for long-term transmission of electric current with minimal value of 20 A. At the end of diploma thesis there was created 3D model of the complete docking station including connectors for charging in program called SolidWorks.
77

Modelling and design of a general purpose, vertical shaft conveyance, all level docking device / Adriaan Johannes Hendrikus Lamprecht

Lamprecht, Adriaan Johannes Hendrikus January 2015 (has links)
Deep level mining is widely practised throughout South Africa, particularly in the gold sector, where the extraordinary depths of vertical hoisting present an array of challenges. The accurate and secure positioning of a conveyance next to a station has been and continues to be one of the unresolved challenges that have led to many serious injuries and equipment damage. The literature study presented in this dissertation highlights some of the complexities associated with properly docking a conveyance and investigates some current, proposed and similar systems to address the issue. From the study it was found that no satisfactory device existed prompting a systematic design of a conveyance arresting device capable of securing a conveyance in a vertical shaft at any level. Proper definition of the system requirements was obtained and summarised into 16 groups. The system requirements play an important role in the design process by setting the direction but also featuring in concept screening and evaluation. In order to generate concepts a variety of creativity inspiring techniques were employed facilitating a systematic search for a solution. Application of the techniques, Brainstorming, Synectics, TRIZ, 2500 Engineering Principles, Sourcebooks and a Morphological chart resulted in the synthesis of 9 concepts. Screening and evaluation was performed on these concepts and the most suitable concept identified. The proposed concept is a simple system where two sets of beams are extended into the shaft in order to have the conveyance settle onto the supporting shaft steelwork. Once the conveyance came to a rest on the steelwork a second set of beams are extended beneath the steelwork to positively lock the conveyance in position. This required the geometric design of the system to ensure adequate strength to satisfy a factor of safety of ten. Design decisions were made on the section properties of the clamp beam by comparing a solid section and a box section. A supporting frame is used to guide the beams, with consideration given to the most appropriate method of attaching this support frame to the conveyance. The first choice was to have the beams extend from the rear of the conveyance but due to the moments and forces involved the conveyance roof structure could not support this configuration. The support frame was instead affixed directly to the conveyance Transom. In order to support the findings of the conventional calculations performed on the system components the system was subjected to finite element analysis. The results obtained from the simulation corresponded well for the simple components and varied somewhat in the more complex shapes attributed to the assumptions made to ease the conventional calculations. Weight and reliability in a harsh shaft environment was identified as critical design parameters and motivated the use of exotic high strength materials. The high strength of the materials made is possible to design a system with practical dimensions of adequate strength supported by the conventional and modelled calculations. Even though high strength materials were used in the design the overall system weigh is dissatisfying. A potentially successful and practical device was designed but certain factors such as weight, cost, conveyance structure and infrastructure modifications threaten the implementation of the design. This dissertation sets a sound foundation for future development and the continued search for a practical simple solution to this age old challenge. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
78

Modelling and design of a general purpose, vertical shaft conveyance, all level docking device / Adriaan Johannes Hendrikus Lamprecht

Lamprecht, Adriaan Johannes Hendrikus January 2015 (has links)
Deep level mining is widely practised throughout South Africa, particularly in the gold sector, where the extraordinary depths of vertical hoisting present an array of challenges. The accurate and secure positioning of a conveyance next to a station has been and continues to be one of the unresolved challenges that have led to many serious injuries and equipment damage. The literature study presented in this dissertation highlights some of the complexities associated with properly docking a conveyance and investigates some current, proposed and similar systems to address the issue. From the study it was found that no satisfactory device existed prompting a systematic design of a conveyance arresting device capable of securing a conveyance in a vertical shaft at any level. Proper definition of the system requirements was obtained and summarised into 16 groups. The system requirements play an important role in the design process by setting the direction but also featuring in concept screening and evaluation. In order to generate concepts a variety of creativity inspiring techniques were employed facilitating a systematic search for a solution. Application of the techniques, Brainstorming, Synectics, TRIZ, 2500 Engineering Principles, Sourcebooks and a Morphological chart resulted in the synthesis of 9 concepts. Screening and evaluation was performed on these concepts and the most suitable concept identified. The proposed concept is a simple system where two sets of beams are extended into the shaft in order to have the conveyance settle onto the supporting shaft steelwork. Once the conveyance came to a rest on the steelwork a second set of beams are extended beneath the steelwork to positively lock the conveyance in position. This required the geometric design of the system to ensure adequate strength to satisfy a factor of safety of ten. Design decisions were made on the section properties of the clamp beam by comparing a solid section and a box section. A supporting frame is used to guide the beams, with consideration given to the most appropriate method of attaching this support frame to the conveyance. The first choice was to have the beams extend from the rear of the conveyance but due to the moments and forces involved the conveyance roof structure could not support this configuration. The support frame was instead affixed directly to the conveyance Transom. In order to support the findings of the conventional calculations performed on the system components the system was subjected to finite element analysis. The results obtained from the simulation corresponded well for the simple components and varied somewhat in the more complex shapes attributed to the assumptions made to ease the conventional calculations. Weight and reliability in a harsh shaft environment was identified as critical design parameters and motivated the use of exotic high strength materials. The high strength of the materials made is possible to design a system with practical dimensions of adequate strength supported by the conventional and modelled calculations. Even though high strength materials were used in the design the overall system weigh is dissatisfying. A potentially successful and practical device was designed but certain factors such as weight, cost, conveyance structure and infrastructure modifications threaten the implementation of the design. This dissertation sets a sound foundation for future development and the continued search for a practical simple solution to this age old challenge. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
79

SIGNAL PROCESSING ALGORITHMS FOR HIGH-PRECISION NAVIGATION AND GUIDANCE FOR UNDERWATER AUTONOMOUS SENSING SYSTEMS

Doonan, Daniel, Utley, Chris, Lee, Hua 10 1900 (has links)
International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / This paper presents an alternative approach to high-precision bearing estimation for navigation and guidance in homing and docking of underwater vehicles. This new technique is significantly simpler than the conventional methods in terms of computation complexity and yet produces results of superior precision and consistency.
80

Optimized planning at a food terminal / Optimerad planering på livsmedelsterminal

Löf, Oskar, Löfgren, Mikael January 2016 (has links)
Bring Frigo transporterar och distribuerar kylda och frysta livsmedel inom Sverige och övriga Norden genom ett temperaturkontrollerat nätverk av fordon, kyllager, fryslager och terminaler. En av Bring Frigo:s terminaler är belägen i Linköping dit livsmedel som ska distribueras till eller från Östergötland ankommer för att lastas om mellan fjärr- och distributionsbilar. Idag räcker kapaciteten på terminalen i Linköping precis till för att kunna hantera det flöde av livsmedel som passerar genom terminalen. Då Bring Frigo nyligen ingått en affär med en större svensk matgrossist om att distribuera matgrossistens livsmedel inom Östergötland i sitt befintliga transportnätverk behöver terminalens kapacitet utökas för att detta ska vara möjligt. I samband med denna förändring vill Bring Frigo passa på att ta fram riktlinjer för hur omlastningsprocessen kan optimeras. Bring Frigo önskar erhålla riktlinjer för vart livsmedlen temporärt ska placeras inne i terminalen under omlastningsprocessen och hur lastbilar ska tilldelas lastkajer så att transportsträckan inne i terminalen hålls så kort som möjligt. Som ett första steg för att besvara var livsmedlen temporärt bör placeras inne i terminalen utformades en intern layout över den tilltänkta ombyggda terminalen. Därefter utvecklades och implementerades en heuristik som, utifrån den framtagna layouten och historiska data över livsmedelsflödet genom terminalen, tog fram var olika livsmedel temporärt bör placeras inne i terminalen och hur tilldelningen av lastkajer bör ske så att erfordrad transportsträcka hålls så kort som möjligt under omlastningsprocessen. Med hjälp av de resultat som erhölls från heuristiken formulerades specifika riktlinjer för respektive arbetsdag. Riktlinjerna för respektive dag delades vidare in i två olika nivåer beroende på om dagen kategoriserades som en dag med normal eller hög arbetsnivå utifrån totala antalet lastbärare som förväntas passera terminalen den aktuella dagen. Slutsatsen av studien är att de riktlinjer som utformats för omlastningsprocessen på terminalen bör reducera den erfordrade transportsträckan av livsmedel inne på terminalen och på så sätt effektivisera omlastningsprocessen, men att detta inte kan säkerställas i och med att historiska data använts som indata till heuristiken.

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