The scope of the presented master thesis was the experimental study of multi-filament yarns made of AR-glass and used for textile-reinforced concrete. The behavior under the tensile loading was investigated by laboratory tests. A high number of yarn specimens (over 300) of six different lengths (from 1 cm to 74 cm) was tested to obtain statistically significant data which were subsequently corrected and statistically processed. The numerical model of the multi-filament bundle was studied and applied for prediction of the yarn performance and for later results interpretation. The model of n parallel filaments describes the behavior of a bundle with varying parameters representing different sources of disorder of the response and provides the qualitative information about the influence of their randomization on the overall bundle response. The aim of the carried experiment was to validate the model presumptions and to identify the model parameters to fit the real load-displacement curves. Unfortunately, due to unsuccessful correction of measured displacements devalued by additional non-linear contribution of the unstiff experiment device the load-displacement diagrams were not applicable to model parameters identification. The statistical evaluation was carried only for the maximal load values and the effect of the specimen size (length) on its strength was demonstrated. The size effect curve did not exclude the existence of spatial correlation of material mechanical properties modifying the classical statistical Weibull theory.

Lagrangian relaxation is a successful solution approach for many combinatorial optimisation problems, one of them being the train timetabling problem (TTP). We model this problem using time expanded networks for the single train schedules and coupling constraints to enforce restrictions like station capacities and headway times. Lagrangian relaxation of these coupling constraints leads to shortest path subproblems in the time expanded networks and is solved using a proximal bundle method. However, large instances of our practical partner Deutsche Bahn lead to computationally intractable models. In this thesis we develop two new algorithmic techniques to improve the solution process for this kind of optimisation problems. The first new technique, Dynamic Graph Generation (DGG), aims at improving the computation of the shortest path subproblems in large time expanded networks. Without sacrificing any accuracy, DGG allows to store only small parts of the networks and to dynamically extend them whenever the stored part proves to be too small. This is possible by exploiting the properties of the objective function in many scheduling applications to prefer early paths or due times, respectively. We prove that DGG can be implemented very efficiently and its running time and the size of nodes that have to be stored additionally does not depend on the size of the time expanded network but only on the length of the train routes. The second technique is an asynchronous and parallel bundle method (APBM). Traditional bundle methods require one solution of each subproblem in each iteration. However, many practical applications, e.g. the TTP, consist of rather loosely coupled subproblems. The APBM chooses only small subspaces corresponding to the Lagrange multipliers of strongly violated coupling constraints and optimises only these variables while keeping all other variables fixed. Several subspaces of disjoint variables may be chosen simultaneously and are optimised in parallel. The solutions of the subspace problem are incorporated into the global data as soon as it is available without any synchronisation mechanism. However, in order to guarantee convergence, the algorithm detects automatically dependencies between different subspaces and respects these dependencies in future subspace selections. We prove the convergence of the APBM under reasonable assumptions for both, the dual and associated primal aggregate data. The APBM is then further extended to problems with unknown dependencies between subproblems and constraints in the Lagrangian relaxation problem. The algorithm automatically detects these dependencies and respects them in future iterations. Again we prove the convergence of this algorithm under reasonable assumptions. Finally we test our solution approach for the TTP on some real world instances of Deutsche Bahn. Using an iterative rounding heuristic based on the approximate fractional solutions obtained by the Lagrangian relaxation we are able to compute feasible schedules for all trains in a subnetwork of about 10% of the whole German network in about 12 hours. In these timetables 99% of all passenger trains could be scheduled with no significant delay and the travel time of the freight trains could be reduced by about one hour on average.

<p>Simultaneous localization and mapping (SLAM) is a general device localization technique that uses realtime sensor measurements to develop a virtualization of the sensor's environment while also using this growing virtualization to determine the position and orientation of the sensor. This is useful for augmented reality (AR), in which a user looks through a head-mounted display (HMD) or viewfinder to see virtual components integrated into the real world. Visual SLAM (i.e., SLAM in which the sensor is an optical camera) is used in AR to determine the exact device/headset movement so that the virtual components can be accurately redrawn to the screen, matching the perceived motion of the world around the user as the user moves the device/headset. However, many potential AR applications may need access to more than device localization data in order to be useful; they may need to leverage environment data as well. Additionally, most SLAM solutions make the naive assumption that the environment surrounding the system is completely static (non-moving). Given these circumstances, it is clear that AR may benefit substantially from utilizing a SLAM solution that detects objects that move in the scene and ultimately provides localization data for each of these objects. This problem is known as the dynamic SLAM problem. Current attempts to address the dynamic SLAM problem often use machine learning to develop models that identify the parts of the camera image that belong to one of many classes of potentially-moving objects. The limitation with these approaches is that it is impractical to train models to identify every possible object that moves; additionally, some potentially-moving objects may be static in the scene, which these approaches often do not account for. Some other attempts to address the dynamic SLAM problem also localize the moving objects they detect, but these systems almost always rely on depth sensors or stereo camera configurations, which have significant limitations in real-world use cases. This dissertation presents a novel approach for registering and localizing unknown moving objects in the context of markerless, monocular, keyframe-based SLAM with no required prior information about object structure, appearance, or existence. This work also details a novel deep learning solution for determining SLAM map initialization suitability in structure-from-motion-based initialization approaches. This dissertation goes on to validate these approaches by implementing them in a markerless, monocular SLAM system called LUMO-SLAM, which is built from the ground up to demonstrate this approach to unknown moving object registration and localization. Results are collected for the LUMO-SLAM system, which address the accuracy of its camera localization estimates, the accuracy of its moving object localization estimates, and the consistency with which it registers moving objects in the scene. These results show that this solution to the dynamic SLAM problem, though it does not act as a practical solution for all use cases, has an ability to accurately register and localize unknown moving objects in such a way that makes it useful for some applications of AR without thwarting the system's ability to also perform accurate camera localization.</p>

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Le problème d’ordre linéaire (LOP) a reçu beaucoup d’attention dans différents domaines d’application, allant de l’archéologie à l’ordonnancement en passant par l’économie et même de la psychologie mathématique. Ce problème est aussi connu pour être parmi les problèmes NP-difficiles. Nous considérons dans cette thèse une variante de (LOP) sous contrainte de cardinalité. Nous cherchons donc un ordre linéaire d’un sous-ensemble de sommets du graphe de préférences de cardinalité fixée et de poids maximum. Ce problème, appelé (FCLOP) pour ’fixed-cardinality linear ordering problem’, n’a pas été étudié en tant que tel dans la littérature scientifique même si plusieurs applications dans les domaines de macro-économie, de classification dominante ou de transport maritime existent concrètement. On retrouve en fait ses caractéristiques dans les modèles étendus de sous-graphes acycliques. Le problème d’ordre linéaire est déjà connu comme un problème NP-difficile et il a donné lieu à de nombreuses études, tant théoriques sur la structure polyédrale de l’ensemble des solutions réalisables en variables 0-1 que numériques grâce à des techniques de relaxation et de séparation progressive. Cependant on voit qu’il existe de nombreux cas dans la littérature, dans lesquelles des solveurs de Programmation Linéaire en nombres entiers comme CPLEX peuvent en résoudre certaines instances en moins de 10 secondes, mais une fois que la cardinalité est limitée, ces mêmes instances deviennent très difficiles à résoudre. Sur les aspects polyédraux, nous avons étudié le polytope de FCLOP, défini plusieurs classes d’inégalités valides et identifié la dimension ainsi que certaines inégalités qui définissent des facettes pour le polytope de FCLOP. Nous avons introduit un algorithme Relax-and-Cut basé sur ces résultats pour résoudre les instances du problème. Dans cette étude, nous nous sommes également concentrés sur la relaxation Lagrangienne pour résoudre ces cas difficiles. Nous avons étudié différentes stratégies de relaxation et nous avons comparé les bornes duales par rapport à la consolidation obtenue à partir de chaque stratégie de relâcher les contraintes afin de détecter le sous-ensemble des contraintes le plus approprié. Les résultats numériques montrent que nous pouvons trouver des bornes duales de très haute qualité. Nous avons également mis en place une méthode de décomposition Lagrangienne. Dans ce but, nous avons décomposé le modèle de FCLOP en trois sous-problèmes (au lieu de seulement deux) associés aux contraintes de ’tournoi’, de ’graphes sans circuits’ et de ’cardinalité’. Les résultats numériques montrent une amélioration significative de la qualité des bornes duales pour plusieurs cas. Nous avons aussi mis en oeuvre une méthode de plans sécants (cutting plane algorithm) basée sur la relaxation pure des contraintes de circuits. Dans cette méthode, on a relâché une partie des contraintes et on les a ajoutées au modèle au cas où il y a des de/des violations. Les résultats numériques montrent des performances prometteuses quant à la réduction du temps de calcul et à la résolution d’instances difficiles hors d’atteinte des solveurs classiques en PLNE. / Linear Ordering Problem (LOP) has receive significant attention in different areas of application, ranging from transportation and scheduling to economics and even archeology and mathematical psychology. It is classified as a NP-hard problem. Assume a complete weighted directed graph on V n , |V n |= n. A permutation of the elements of this finite set of vertices is a linear order. Now let p be a given fixed integer number, 0 ≤ p ≤ n. The p-Fixed Cardinality Linear Ordering Problem (FCLOP) is looking for a subset of vertices containing p nodes and a linear order on the nodes in S. Graphically, there exists exactly one directed arc between every pair of vertices in an LOP feasible solution, which is also a complete cycle-free digraph and the objective is to maximize the sum of the weights of all the arcs in a feasible solution. In the FCLOP, we are looking for a subset S ⊆ V n such that |S|= p and an LOP on these S nodes. Hence the objective is to find the best subset of the nodes and an LOP over these p nodes that maximize the sum of the weights of all the arcs in the solution. Graphically, a feasible solution of the FCLOP is a complete cycle-free digraph on S plus a set of n − p vertices that are not connected to any of the other vertices. There are several studies available in the literature focused on polyhedral aspects of the linear ordering problem as well as various exact and heuristic solution methods. The fixed cardinality linear ordering problem is presented for the first time in this PhD study, so as far as we know, there is no other study in the literature that has studied this problem. The linear ordering problem is already known as a NP-hard problem. However one sees that there exist many instances in the literature that can be solved by CPLEX in less than 10 seconds (when p = n), but once the cardinality number is limited to p (p < n), the instance is not anymore solvable due to the memory issue. We have studied the polytope corresponding to the FCLOP for different cardinality values. We have identified dimension of the polytope, proposed several classes of valid inequalities and showed that among these sets of valid inequalities, some of them are defining facets for the FCLOP polytope for different cardinality values. We have then introduced a Relax-and-Cut algorithm based on these results to solve instances of the FCLOP. To solve the instances of the problem, in the beginning, we have applied the Lagrangian relaxation algorithm. We have studied different relaxation strategies and compared the dual bound obtained from each case to detect the most suitable subproblem. Numerical results show that some of the relaxation strategies result better dual bound and some other contribute more in reducing the computational time and provide a relatively good dual bound in a shorter time. We have also implemented a Lagrangian decomposition algorithm, decom-6 posing the FCLOP model to three subproblems (instead of only two subproblems). The interest of decomposing the FCLOP model to three subproblems comes mostly from the nature of the three subproblems, which are relatively quite easier to solve compared to the initial FCLOP model. Numerical results show a significant improvement in the quality of dual bounds for several instances. We could also obtain relatively quite better dual bounds in a shorter time comparing to the other relaxation strategies. We have proposed a cutting plane algorithm based on the pure relaxation strategy. In this algorithm, we firstly relax a subset of constraints that due to the problem structure, a very few number of them are active. Then in the course of the branch-and-bound tree we verify if there exist any violated constraint among the relaxed constraints or. Then the characterized violated constraints will be globally added to the model. (...)

Introduction: Central Line-Associated Bloodstream Infections (CLABSIs) are a major cause of increased mortality, morbidity and healthcare costs in neonatal intensive care units (NICUs) patients. Despite CDC's efforts to reduce infection rates, patients often suffer consequences. The objective of this study is to perform a systematic review of strategies utilized in the neonatal population and evaluate them with the current CDC's guidelines to assess the effectiveness of bundles in preventing CLABSI in NICUs. Methods: A systematic literature search was conducted using CINAHL Plus with Text, Cochrane Database of Systematic Reviews and MEDLINE from January 2008 up to 2018. There were multiple search terms used and these included "neonate OR newborn OR infant", "CLABSI OR central line-associated bloodstream infection", "intervention OR prevention" and "bundle". The search solely focused on the outcome of infant patients. Therefore studies were excluded for the following criteria: being non-peer reviewed, being published before 2008, and being a case in which CLABSI was assessed in patients outside the NICU. See Table 4 and 5 for further information. Results: Eight articles were eligible for inclusion all of which CDC's guidelines were implemented in their strategy of intervention. The systematic review showed that adherence to care bundles decreases infection rates drastically. All eight articles reported a significant decrease in CLABSI rates following the implementation of the bundle set by CDC with two studies achieving a CLABSI rate of zero. Author's Conclusion: Implementation of care bundles showed a success in reducing CLABSI rates in the NICUs; however none of the studies endorsed a specific bundle application utilized to achieve its intended goal. Some practices adopted CDC's guidelines more than others and those showed a greater decrease in infection rate. In addition, it is evident that nurses deliver the best care when preventing an infection. Further research is needed to assess the effectiveness of a specific bundle element.

Recent accessibility drives and price wars between the major South African (SA) cell phone companies suggest that the landscape for the adoption of mobile learning (m-learning) at the Higher Education Institution (HEI) level may be changing. As such, there is a need to gauge the current mobile readiness of students for m-learning. Mobile technology readiness refers to the extent to which students have access to mobile devices (not only handsets), and can afford data bundles that meet or exceed the requirements of a base set of currently available m-learning applications (Naicker and Van der Merwe 2012). Mobile operational readiness refers to students’ awareness of, attitude towards, support and training that is required for m-learning. This study conducted an assessment of the technology and operational readiness of students at a SA HEI. An in-depth literature survey was undertaken to delineate technology and operational readiness of students for m-learning. For technology readiness, an investigation was conducted on m- learning applications that are currently available and the technology requirements of these mobile applications. This was undertaken to determine the extent that the current student mobile handset profile match these requirements. The literature review also included a search for mobile opeeratratiioonnaall ffaactorctorss ssuuchch aass ssttuuddeennttss’’ aawwaarenerenessss ooff aanndd aattttiittuuddee ttoowwaarrddss mm--lleaearrnininngg as well as m-learning support and training that students require. The philosophical underpinning of this study was based on Activity Theory. The strategy of inquiry employed was a case study approach. Data was collected from students at the Durban University of Technology, a resident based SA HEI. A mixed methods data collection strategy was employed. The researcher used a field survey questionnaire as the primary research instrument to assess mobile technology and operational readiness. Focus group interviews were used as a secondary data gathering tool to triangulate and strengthen the results. The results were presented using descriptive and inferential statistics and were analyzed using the lens of activity theory. In terms of technology readiness, despite a high level of ownership and reasonable compliance with application requirements, data costs remain prohibitive. In assessing operational readiness, despite a positive attitude, the majority of the students require awareness, ongoing support and training. Several recommendations based on the findings are offered. For example, one of the findings showed that mobile connectivity affordability was low amongst students and it is recommended that the HEI work around exorbitant connectivity costs by combining m-learning technologies to form meaningful m-learning approaches at a minimum v cost. Another finding showed low awareness of m-learning at the HEI. A recommendation advanced to combat this finding is for the HEI to encourage and support dialogue among key stakeholders. This study concludes that any m-learning endeavour to implement m-learning at this HEI is bound to fail as only a small percentage of students are aware of m-learning and can afford data bundles to implement m-learning in its true sense. As an implication of this study to other HEI’s, the researcher suggests that regular mobile readiness surveys be conducted. / Science and Technology Education / M. A. (Information Systems)

熱像儀，能感測可見光感測器無法取得的訊息，因此若能透過熱像儀器進行環境偵測，便能得到一般可見光感測器無法獲取的資料。本研究擬以四旋翼UAS酬載熱像儀得到局部區域高解析度之地面熱資訊以便作為地溫研究之背景資料使用。而一般地溫研究區，不易佈設控制點，因此本研究除於無人機上酬載熱像儀之外，並將搭載Trimble BD970 GNSS OEM接收模組，嘗試以少量地面控制點、以及GNSS動態後處理的方式取得取像時對應的GNSS觀測量輔助熱像定位定向。本研究中針對國立政治大學旁的指南溪實驗區與陽明山國家公園的小油坑實驗區，使用AI-RIDER YJ-1000-HC四旋翼UAS分別酬載熱像儀FLIR Tau 640和巨哥XM6，並且同時搭載Trimble BD970 GNSS OEM接收模組、以及GNSS動態後處理的方式取得取像時對應的GNSS觀測量搭配少量地面控制點輔助熱像定位定向，過程中透過三焦張量剔除自動匹配之誤匹配連結點。實驗結果顯示，兩實驗區所產製之DSM於不易變動區域精度經現有資料檢核均在±1m，而指南溪實驗區產製出地面解析度11公分的數值表面模型(Digital Surface Model, DSM)與正射熱像，且正射熱像平面精度達為47公分；小油坑實驗區產製出地面解析度14公分之DSM與正射熱像，正射熱像平面精度則為67公分，雖然DSM和正射熱像精度無法符合一般常規的測量規範，但成果仍然可以證明熱像直接產製DSM以及正射熱像之可行性，兩實驗區最後皆生成數值溫度表面模型(Digital Surface Temparature Model, DSTM)，顯示本研究所提方法之可行性，所生成之成果可供後續地溫研究使用。 / Thermal infrared images show the temperature change of sensed scenes. Therefore, thermal infrared camera can sense some important information that optical digital cameras cannot do for the environment monitoring. In this study, the Quadcopter UAS for thermal image collection applied to geothermal study will be developed. FIIR Tau 640 and Magnity Eletric XM6 thermal infrared sensor will be used in this thermal image collection system separately two test areas, Zhinan River nearby NCCU and Xiaoyoukeng, in the Yangmingshan National Park. Additionally, Trimble BD970 GNSS OEM board will be carried on the Quadcopter UAS to collect dual-frequency GNSS observations for determining the flying trajectory by Post-processed kinematic (PPK) technique to support the positioning and orientating of collected thermal images, and the trifocal tensor will be used to delete wrong matching tie images points. From the tests, the differences between produced DSM and existing DSM data are ± 1 m on uneasy change ground surface in two test areas. The resolution of produced DSM and thermal orthoimages are about 11 cm in Zhinan River, and 14cm in Xiaoyoukeng area. The accuracy of thermal orthoimages is 47cm in Zhinan River and 67cm in Xiaoyoukeng area. The accuracy of thermal orthoimages may not comply with a normal surveying standard, but it proves the possibility of DSM and orthorectifed thermal images generated from thermal images directly. Digital Surface Temparature Model (DSTM) produced in both tests can be used for volcanic geothermal monitoring in the future.

Les principaux objets étudiés dans cette thèse sont les équations décrivant le morphisme de groupe sur une variété abélienne, plongée dans un espace projectif, et leurs applications en cryptographie. Notons g sa dimension et k son corps de définition. Ce mémoire est composé de deux parties. La première porte sur l'étude des courbes d'Edwards, un modèle pour les courbes elliptiques possédant un sous-groupe de points k-rationnels cyclique d'ordre 4, connues en cryptographie pour l'efficacité de leur loi d'addition et la possibilité qu'elle soit définie pour toute paire de points k-rationnels (loi d'addition k-complète). Nous en donnons une interprétation géométrique et en déduisons des formules explicites pour le calcul du couplage de Tate réduit sur courbes d'Edwards tordues, dont l'efficacité rivalise avec les modèles elliptiques couramment utilisés. Cette partie se conclut par la génération, spécifique au calcul de couplages, de courbes d'Edwards dont les tailles correspondent aux standards cryptographiques actuellement en vigueur. Dans la seconde partie nous nous intéressons à la notion de complétude introduite ci-dessus. Cette propriété est cryptographiquement importante car elle permet d'éviter des attaques physiques, comme les attaques par canaux cachés, sur des cryptosystèmes basés sur les courbes elliptiques ou hyperelliptiques. Un précédent travail de Lange et Ruppert, basé sur la cohomologie des fibrés en droite, permet une approche théorique des lois d'addition. Nous présentons trois résultats importants : tout d'abord nous généralisons un résultat de Bosma et Lenstra en démontrant que le morphisme de groupe ne peut être décrit par strictement moins de g+1 lois d'addition sur la clôture algébrique de k. Ensuite nous démontrons que si le groupe de Galois absolu de k est infini, alors toute variété abélienne peut être plongée dans un espace projectif de manière à ce qu'il existe une loi d'addition k-complète. De plus, l'utilisation des variétés abéliennes nous limitant à celles de dimension un ou deux, nous démontrons qu'une telle loi existe pour leur plongement projectif usuel. Finalement, nous développons un algorithme, basé sur la théorie des fonctions thêta, calculant celle-ci dans P^15 sur la jacobienne d'une courbe de genre deux donnée par sa forme de Rosenhain. Il est désormais intégré au package AVIsogenies de Magma. / The main objects we study in this PhD thesis are the equations describing the group morphism on an abelian variety, embedded in a projective space, and their applications in cryptograhy. We denote by g its dimension and k its field of definition. This thesis is built in two parts. The first one is concerned by the study of Edwards curves, a model for elliptic curves having a cyclic subgroup of k-rational points of order 4, known in cryptography for the efficiency of their addition law and the fact that it can be defined for any couple of k-rational points (k-complete addition law). We give the corresponding geometric interpretation and deduce explicit formulae to calculate the reduced Tate pairing on twisted Edwards curves, whose efficiency compete with currently used elliptic models. The part ends with the generation, specific to pairing computation, of Edwards curves with today's cryptographic standard sizes. In the second part, we are interested in the notion of completeness introduced above. This property is cryptographically significant, indeed it permits to avoid physical attacks as side channel attacks, on elliptic -- or hyperelliptic -- curves cryptosystems. A preceeding work of Lange and Ruppert, based on cohomology of line bundles, brings a theoretic approach of addition laws. We present three important results: first of all we generalize a result of Bosma and Lenstra by proving that the group morphism can not be described by less than g+1 addition laws on the algebraic closure of k. Next, we prove that if the absolute Galois group of k is infinite, then any abelian variety can be projectively embedded together with a k-complete addition law. Moreover, a cryptographic use of abelian varieties restricting us to the dimension one and two cases, we prove that such a law exists for their classical projective embedding. Finally, we develop an algorithm, based on the theory of theta functions, computing this addition law in P^15 on the Jacobian of a genus two curve given in Rosenhain form. It is now included in AVIsogenies, a Magma package.